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Srst Dominaiit ^'arie^of Man. 
MieditaiTanese (^) with R)ur Races, 

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Second Dominant "Vftriety of Maii|. 
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l':Ei/jh Asians, T-JIralians. 

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Hypothetical Sketch 

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TTonophylEtic origin 

aauiof Ae extensitinof thelZEacesofMan 
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VOL. n. 


549 <Ss 551 BROADWAY. 



r-'' 1 S'O 

A sense suoiTino 
Of snmethinn; far more deeply iiiteil'iiwil, 
Wliose duelling is the light of setting siuia, 
And the ronnd oeean, and the living air, 
And tlio blue elry, and in the mind of man ; 
A motion and a spirit that impels 
All thinking things, all objects of all thought, 
And rolls throngh all things. 

In all things, in all natures, in the stars 
Of azure heaven, the uucnduring clouds., 
In flower and tree, in every pebbly stone 
'I'liat paves tlie brooks, tlie stationary rocks, 
The moving waters and the invisible air. 







Eeforra of Systems by the Theory of Descent. — The Natural System as a 
Pedigree. — ralreontological Eecords of the Pedigree. — Petrifactions 
as Eecords of Creation. — Deposits of the Nej^tunio Strata and the 
Enclosure of Oi'ganic Remains. — Division of the Organic History of 
the Eartli into Five Main Periods : Period of the Tangle Forests, 
Fern Forests, Pine Forests, Foliaoeous Forests, and of Cultivation. — 
The Series of Neptunic Strata. — Immeasurable Duration of the 
Periods ■which have elapsed daring their Formation. — Deposits of 
Strata only during the Sinking, not during the Elevation of the 
Ground. — Other Gaps in the Eecords of Creation. — Metamorpliic 
Condition of the most Ancient Neptunic Strata. — Small Extent of 
PaliEontological Experience. — Small proportion of Organisms and 
of I'arts of Organisms Capable of Petrifying. — Rarity of many 
Petriiied Species. — Want of Fossilised Intermediate Forms. — 
Eecords of the Creation in Ontogeny and in Comparative 




Special Mode of Carrying out the Theory of Descent in the Natural 
System of Organisms. — Construction of Pedigrees. — Descent of all 
Many-celled from Single-celled Organisms. — Descent of Cells 
from Monera. — Meaning of Organic Tribes, or Phyla. — Number of 
the Tribes in the Animal and Vegetable Kingdoms. — The Monophy- 
letio Hypothesis of Descent, or the Hypothesis of one Common 
Progenitor, and the Polyphyletio Hypothesis of Descent, or the 
Hypothesis of many Progenitors. — The Kingdom of Protista, or 
Primasval Beings. — Eight Classes of the Protista Kingdom: 
Monera, Amojbre, or Protoplasta; ; Whip-swimmers, or Flagellata; 
atcd-balls, or Cili Catallacta ; Labyrinth-streamers, or Labyrinth- 



ulea; ; Flint-cells, or Diatomcie ; Mucous-moulds, or Myxomycetes ; 
Root-footers (Ehizopoda). — Eemarks on the General Natural History 
of the Protista: Their Vital Phenomena, Chemical Composition, 
and Formation (Individuality and Fundamental Form). — I'hylogeny 
of the Prostiata Kingdom , 8G 



The Natural System of the Vegetable Kingdom. — Division of the Vege- 
table Kingdom into Six Branches and Eighteen Classes. — The 
Flowcrloss Plants (Cryptogamia). — Sub-kingdnm of the Thallus 
Plants. — The Tangles, or Algic (Primary Algic, Green Algie, Brown 
Algie, Red Alga;.) — The Threud-jilauts, or Inopbytes (Lichens and 
Fungi). — Sub-kingdom of the Prothallus Plants.— ^Tho Mosses, or 
Muscinoe (Water-mosses, Liverworts, Leaf-mosses, Bog-mosses). — 
The Ferns, or Filicina) (Leaf-ferns, Bamboo- ferns, Water-ferns, 
Scale-ferns).— Sub-kingdom of Flowering Plants (Phanerogamia). — 
The Gymnosperms, or Plants with Naked Seeds (Palm-ferns 
= Cycadea! ; Pines =^ Coniferae.) — The Angiospcrms, or Plants with 
Enclosed Seeds. — Monoeotylio. — DiootyUc. -Cup-blossoms (Apc- 
talie). — Star-bloBBoms (Diapetalie). — Bell-blossoms (Gumopetalaj) 77 



I. Animal-Plants and Woiisig. 

'lice Natural System of the Animal Kingdom. — Linnfous and Lamarck's 
Systems. — The Four Types of Biir and Cuvier. — T'heir Increase to 
Seven Types. — Genealogical Importance of the 'Seven Types as 
Independent Tribes of the Animal Kingdom. — Derivation of 
Zoophytes and Worms from Primeval Animals. — Monopliyletic and 
Polyphyletio Hypothesis of the Descent of the Animal Kingdom, 
— Common Origin of the Four Higher Animal Tribes out of the Worm 
Tribe. — Division of tlio Seven Animal Tribes into Sixteen Main 
Classes, and Thirty-eight Classes. — Primajval Animals (Mouera, 
Amojbce, Synamceba^), Gregarines, Infusoria, Plaaa^ades, and Gas- 
trcoadcs (Planula and Castrula). — Tribe of Zoophytes. — Spongias 
(Mucous Sponges, Fibrous Sponges, Calcareous Sponges). — Sea 
Nettles, or Acalephas Corals, Hood jellies. Comb-jellies). — Tribe of 
Worms 117 





II. MoLLUscA, Stak-Fishes, and Akticulated Animals. 

Tribe of Mollusos. — Four Classes of Molluscs : Lamp-shells (Spirobran- 
chia); Mussels (Lamellibrancliia) ; Snails (Coclilides) ; Cuttle-fish 
(Cephalopoda). — Tribe of Star- fishes, or Eohinoderma. — Their Deri- 
vation from Eingcd Worms (Mailed Worms, or Phracthelrainthes). — 
The Alternation of Generation in the Echlnoderma. — Four Classes 
of Star-fish: Sea-stars (Asteridea); Sea-lilies (Crinoide-a) ; Sea- 
urchins (Echinidea); Sea-cucumbers (Holothuridca). — Tribe of 
Articulated Animals, or Arthropoda. — Four Classes of Articulated 
Animals : Branohiata, or Crustacea, breathing through gills ; 
Jointed Crabs; Mailed Crabs; Articulata Traoheata, breathing 
through Air Tubes. — Spiders (Long Spiders, Eound Spiders). — 
Myriopods. — Insects. — Chewing and Sucking Insects. — Pedigree 
ajid History of the Eight Orders of Insects 151 



III. Verteekate Animals. 

The Records of the Creation of Vertebrate Animals (Comparative 
Anatomy, Embryology, and Palajontology). — The Natural System of 
Vertebrate Animals. — The Four Classes of Vertebrate Animals, 
according to Linnajus and Lamarck. — Their Increase to Nine 
Classes. — Main Class of the Tube-hearted, or Skull-less Animals (the 
Lancelet). — Blood Relationship between the Skull-less Fish and the 
Tunicates. — Agreement in the Embryological Development of Am- 
phioxus and Asoidise. — Origin of the Vertebrate Tribe out of the 
Worm Tribe. — Main Class of Single-nostriled, or Round-mouthed 
Animals (Hag and Lampreys). — Main Class of Anamnionate Ani- 
mals, devoid of Amnion. — Fishes (Primasval Fish, Cartilaginous 
Fish, Osseous Fish). — Mud-fish, or Dipneusta. — Sea Dragons, or 
Halisauria. — Frogs and Salamanders, or Amphibia (Mailed 
Amphibia, Naked Amphibia). — Main Class of Aranionate Animals, 
or Amniota. — Reptiles (Primary Reptiles, Lizards, Serpents, Croco- 
diles, Tortoises, Flying Reptiles, Dragons, Beaked Reptiles), — Birds 
(Feather-tailed, Fan-tailed, Bush-tailed.) ... ., 192 




IV. Mammals. 


Tlie System of Mammals accordiTig; to Lintiajus and Blainville. — Three 
Sub-classes of Mammals (Ornithodelphia, Didelphia, Monodelphia). 
— Ornithodolphia, or Monotrema. — Beaked Animals (Ornithostoma). 
— Didelphia, or Marsupials. — Herbivorous and Carnivorous Marsu- 
pials. — Monodelphia, or Placentalia (Placental Animals). — Meaning 
of the Placenta. — Tuft Placentalia. — Girdle Placentalia. — Disc Pla- 
centalia. — Non-deciduates, or Indeoiduata. — Hoofed Animals. — • 
Single and Double-hoofed Animals. — Whales. — Toothless Animals. 
— Deciduates, or Animals with Decidua. — Semi-apes. — Gnawing 
Animals. — Pseudo-hoofed Animals. — Inseotivora. — Beasts of Prey. 
— Bats. — Apes „ 231 



The Application of the Theory of Descent to Man. — Its Immense Im- 
portance aud Logical Necessity. — Man's Position in the Natural 
System of Animals, among Disco-placental Anii^ls. — Incorrect 
Separation of the Bimana and Quadruraana. — Correct Separation of 
Semi-apes from Apes. — Man's Position in the Order of Apes. — 
Narrow nosed Apes (of the Old World) and Flat-nosed Apes (of 
America). — Dillcrencc of the two Groups. — Origin of Man from 
Narrow-nosed Apes. — Human Apes, or Anthropoides. — African 
Human-apes (Gorilla and Chimpanzee). — Asiatic Human-apes 
(Orang and Gibbon). — Comparison between the diiferent Iluman 
Apes and the different Eaces of Men. — Survey of the Series 
of the Progenitors of Man. — Invertebrate Progenitors (Prochordata) 
and Vertebrate Progenitors 263 



Age of the Human Eace. — Causes of its Origin. — The Origin of Human 
Language. — Monophyletio or Single, Polyphyletio or Multiple 

Origin of the Human Race. — Derivation of Man from many Pairs. 

Classification of the Human Eaces. — System of Twelve Species of 
Men.— Woolly-Haired Men, or Ulotrichis.— Bushy-Haired (Papuans, 



Hottentots.) — ^Pleecy-hdired (Caffrcs, Negroes). — Straiglit-haired 
Men, or Lissotriclu. — Stiff-haired (Australians, Malays, Mongols, 
Arctic, and Americau Tribes). — Curly-haired (Dravidas, Nubians, 
Midlanders). — Number of Population. — Primeval Home of Man 
(South Asia, or Lemuria). — Nature of Primajval Men. — Number of 
Primffival Languages (Monoglottists and Polyglottists). — Divergence 
and Migration of the Human Race. — Geographical Distribution of 
the Human Species ... ... ,.. ... ,., ... ... 29G 



Objections to the Doctrine of Filiation. — Objections of Faith and 
Reason. — Immeasurable Length of the Geological Periods. — Transi- 
ion Forms between Kindred Species. — Dependence of Stability of 
Form on Inheritance, and of the Variability of Form on Adaptation. — 
Origin of very Complicated Arrangement of Organisation. — Gradual 
Development of Instincts and Mental Activities. — Origin of a priori 
Knowledge from Knowledge a posteriori. — The Knowledge requisite 
for the Correct Understanding of the Doctrine of Filiation. — Neces- 
sary Interaction between Empiricism and Philosophy. — Proofs of the 
Theory of Descent. — Inner Causal-Connection between all the Bio- 
logical Series of Phenomena. — The Direct Proof of tlie Theory of 
Selection. — Relation of the Theory of Descent to Anthropology. — 
Proofs of the Animal Origin of Man. — The Pithecoid Theory as an 
Inseparable Part of the Theory of Descent. — Induction and Deduc- 
tion. — Gradual Development of the Human Mind. — Body and Mind. 
— Human Soul and Animal Soul. — A Glance at the Future ... 334 

Ltst of Works nEFEKRisD to in the Text 371 

Appendix (Exi)lanation of the Plates) ,,, __ 379 

Indqx ... ... ... .,, .„ ,^, ^_^ 402 






170, 171 

• » 

174, 175 

• w 

201, 202 



XV. — Hypothetical Sketch of the Monophyletic Origin of Frontispiece 

IV. — Hand of Nine different Mammals .. To face jpage 34 

V. — Single-Stemmed, or Monophyletic, Pedigree of tlie 

Vegetable Kingdom „ 112 

VI. — Historical Growth of the Six Great Stems of Animals „ 122 

VII. — Animal Plants, or Zoophytes 
Vlll. — Star Fishes — First Generation i 
IX. — Star Fishes — Second Generation S 
X. — Nauplius-Youth-Form of Six Crab Fish 
XI. — Adult-Form of the same Six Crab Fish 
XII. — Ascidia and Amphioxus 
XIII. — Ascidia and Amphioxus 
XIV. — Single, or Monophyletic, Pedigree of Cack-boned 

Animals ... To face page i'22 


8. — ^Protaroreba Primitiva 52 

9. — Bathybius Hojckelii ... ... ... ... ... ,„ ,,. 5". 

10. — Amoeba Sphserococcus , fti 

11. — Euglena Striata ... ... ... ... ... ... ... ... 57 

12. — Magosphfera Plauula 58 

13. — Labyrinthula Maorocystis 59 

14. — Navicula Hippocampus ... ... ... ... GO 

15. — Physarum Albipes 61 

16.-^CyrtidospIisBra Echinoides GG 

17. — Caulerpa Denticulata ... ... ,„ ,., __ gy 

18. — Euastrum Kota ... ... ... ,,, ,., ,., ^__ §3 

19. — Fuous Vesioulosus (egg of) , go 




Heform of Systems by the Tlieory of Descent, — The Natural System as a 
Pedigree. — Palaeontological Records of the Pedigree. — Petrifactions as 
Records of Creation. — Deposits of the Neptunio Strata and the 
Enclosure of Organic Remains. — Division of the Organic History of 
the Earth into Five Main Periods : Period of the Tangle Forests, Fern 
Forests, Pine Forests, Foliaceoua Forests, ajid of Cultivation. — The 
Series of Neptudic Strata. — Immeasurable Duration of the Periods which 
have elapsed during their Formation. — Deposits of Strataonly during the 
Sinking, not during the Elevation of the Ground, — Other Gaps ia the 
Records of Creation.— Metamorphic Condition of the most Ancient 
Neptunic Strata. — Small E.^tent of Palasontological Experience. — 
Small proportion of Organisms and of Parts of Organisms Capable of 
Petrifying. — Rarity of many Petrified Species. — Want of Fossilised 
Intermediate Forms. — Records of the Creation in Ontogeny and in 
Comparative Anatomy. 

The revolutionary influence which the Theory of Descent 
must exercise upon all sciences, "will in all probability affect 
no branch of science, excepting Anthropology, so much as 
the descriptive portion of natural history, that which is 
known as systematic Zoology and Botany. Most naturalists 
who have hitherto occupied themselves with arranging the 
diflerent systems of animals and plants, have collected, named, 
and arranged the different species of these natural bodies 



with much the same interest as antiquarians and ethno- 
graphers collect the weapons and utensils of different nations. 
Many have not even risen above the degree of intelligence 
with which people usually collect, label, and arrange crests, 
stamps, and similar curiosities. In the same manner as 
some collectors find their pleasure in the similarity of forms, 
the beauty or rarity of the crests or stamps, and admire 
in them the inventive art of man, so many naturalists take 
a delight in the manifold forms of animals and plants, and 
marvel at the rich imagination of the Creator, at His 
unwearied creative activity, and at His curious fancy for 
forming, by the side of so many beautiful and useful organ- 
isms, also a number of ugly and useless ones. 

This childlike treatment of systematic Zoology and Botany 
is completely annihilated by the Theory of Descent. In the 
place of the superficial and playful interest with which most 
naturalists have hitherto regarded organic structures, we 
now have the much higher interest of the intelligent under- 
standing which detects in the related forms of organisms 
their true hlood relationships. The Natural System of 
anivxals and plants, which was formerly valued either only 
as a registry of names, to facilitate the survey of the different 
forms, or as a table of contents for the short expression of 
their degrees of similarity, receives from the Theory of 
Descent tlie incomparably higher value of a true pedigree of 
organisms. This pedigree is to disclose to us the genealo- 
gical connection of the smaller and larger groups. It has to 
show us in what way the different classes, orders, families, 
genera, and species of the animal and vegetable kingdoms 
correspond with the different branches, twigs, and gi-oups of 
twigs of the pedigree. Every wider and higher category 


or stage of the system (for example a class, or an order) 
comprises a number of larger and stronger branches of the 
pedigree; every narrower and lower category (for example 
a genus, or a species) only a smaller and thinner group of 
twigs. It is only when we thus view the natural system as 
a pedigree that we perceive its true value. (Gen. Morph. ii. 
Plate XVII. 397.) 

Since we hold fast this genealogical conception of the 
Organic System, to which alone undoubtedly the future of 
classificatory Zoology and Botany belongs, we should now 
turn our attention to one of the most essential, but also one 
of the most difficult, tasks of the " non-miraculous history of 
creation," namely, to the actual construction of the Organic 
Pedigree. Let us see how far we are already able to point 
out all the different organic forms as the divergent descend- 
ants of a single or of some few common original forms. 
But how can we construct the actual pedigree of the 
animal and vegetable group of forms from our knowledge 
of them, at present so scanty and fragmentary ? The answer 
to this question lies in what we have already remarked of 
the parallelism of the three series of development — in the 
important causal relation which connects the palseontolo- 
gical development of all organic tribes with the embryological 
development of individuals, and with the systematic de- 
velopment of groups. 

In order to accomplish our task we shall first have to 
direct our attention to palaeontology, or the science of petri- 
factions. For if the Theory af Descent is really true, if the 
petrified remains of formerly living animals and plants 
really proceed from the extinct primseval ancestors and 
progenitors of the present organisms, then, without any- 


thing else, the knowledge and comparison of petrifactions 
ought to disclose to ua the pedigree of organisms. However 
simple and clear this may seem in theory, the task becomes 
extremely hard and complicated when it is actually taken in 
hand. Its practical solution would be very difficult even 
if the petrifactions were to any extent completely preserved. 
But this is by no means the case. The obvious records of 
creation which lie buried in petrifactions are imperfect 
beyond all measure. Hence it is necessary critically to 
examine these records, and to determine the value which 
petrifactions possess for the history of the development of 
organic tribes. As I have previously discussed the general 
importance of petrifactions as the records of creation, when 
we were considering Cuvier's merits in the science of fossils, 
we may now at once examine the conditions and circum- 
stances under which the remains of organic bodies became 
petrified and preserved in a more or less recognizable form. 

As a rule we find petrifactions or fossils enclosed only 
in those stones which have been deposited in layers as mud 
by water, and which are on that account called neptunic, 
stratified, or sedimentary rocks. The deposition of such 
strata could of course only commence after the condensation 
of watery vapour into liquid water had taken place 
in the course of the earth's history. After that period, 
which we considered in our last chapter, not only did life 
begin on the earth, but also an uninterrupted and exceed- 
incrly important transformation of the rigid inorganic crust 
of the earth. The water be^an that extremely import- 
ant mechanical action by which the sm-face of the earth 
is perpetually, though slowly, transformed. I may surely 
presume that it is generally known what an extremely 


important influence, in this respect, is even yet exercised 
by water at every moment. Aa it falls down as rain, 
trickling througli the upper strata of the earth's crust, 
and flowing down from heights into hollows, it chemically 
dissolves different mineral parts of the ground, and mechani- 
cally washes away the loose particles. In flowing down 
from mountains water carries their debris into the plains, 
or deposits it as mud in stagnant lakes. Thus it con- 
tinually works at lowering mountains and filling up 
valleys. In like manner the breakers of the sea work 
uninterruptedly at the destruction of the coasts and at 
filling up the bottom of the sea with the debris they 
wash down. The action of water alone, if it were not 
counteracted by other circumstances, would in time level the 
whole earth. There can be no doubt that the mountain 
masses — which are annually carried down as mud into the 
sea, and deposited on its floor — are so great that in the 
course of a longer or shorter period, say a few millions 
of years, the surface of the earth would be completely 
levelled and become enclosed by a continuous sheet of water. 
That this does not happen is owing to the perpetual volcanic 
action of the fiery-fluid centre of the earth. The surging of 
the melted nucleus against the firm crust necessitate* con- 
tinual alternations of elevation and depression on the 
diflferent parts of the earth's surface. These elevations and 
depressions for the most part take place very slowly • but, 
as they continue for thousands of years, by the combined 
effect of small, interrupted movements, they produce results 
no less grand than does the counteracting and leveUino- 
action of w^ater. 

Since the elevations and depressions of the different parts 


of the earth alternate with one another in the course of 
millions of years, first this and then that part of the earth's 
surface is above or below the level of the sea. I have 
already given examples of this in the preceding chapter 
(voL L p. 361). Hence, in all probability, there is no part of 
the outer crust of the earth which has not been repeatedly 
above and also below the level of the sea. This repeated 
change explains the variety and the different composition of 
the numerous neptunic strata of rocks, which in most places 
have been deposited one above another in considerable 
thickness. In the different periods of the earth's history 
during which these deposits took place thei e Kved various 
and different populations of animals and plants. When their 
dead bodies sank to the bottom of the waters, the forms of 
the bodies impressed themselves upon the soft mud, and 
imperishable parts, such as hard bones, teeth, shells, etc., 
became enclosed in it uninjured. These were preserved in 
the mud, which condensed them into neptmiic rock, and as 
petrifactions they now serve to characterize the r^jspective 
strata. By a careful comparison of the different strata lying 
one above another, and the petrifactions preserved in them, 
it has become possible to decide the relative age of the 
strata and groups of strata, and to establish, by direct 
observation, the principal eras of phylogeny, that is to say, 
the stages in history of the development of animal and 
vegetable tribes. 

The different strata of neptunic rocks deposited one above 
another, which are composed in very various ways of lime- 
stone, clay, and sand, geologists have grouped together into 
an ideal System or Series, which corresponds with the whole 
course of the organic history of the earth, or with that portion 


of the earth's history durmg which organic life existed. Just 
as so-called " universal history " falls into larger and smaller 
periods, which are characterized by the conditions of de- 
velopment of the most important nations at the respective 
epochs, and are separated from one another by great events, 
so we also divide the infinitely longer organic history of the 
earth into a series of greater and less periods. Each of 
these periods is distinguished by a characteristic flora and 
fauna, and by the specially strong development of certain 
vegetable or animal groups, and each is separated from the 
preceding and suceeediag period by a striking change in 
the character of its animal and' vegetable inhabitants. 

In relation to the following survey of the historical 
course of development which the large animal and vegetable 
tribes have passed through, it wiU be desirable to say a few 
words first as to the systematic classification of the neptunic 
groups of strata, and the larger and smaller periods corres- 
ponding to them. As will be seen directly, we are able to 
divide the whole of the sedimentary rocks lying one above 
another into five main groups or periods, each period into 
several subordinate groups of strata or systems, and each 
system of strata again into still smaller groups or forma- 
tions; fiaslly, each formation can again be divided into 
stages or sub-formations, and each of these again into still 
smaller layers or beds. Each of the five great rock-groups 
was deposited during a great division of the earth's history, 
during a long era or epoch; each system during a shorter 
period ; each formation during a stiU shori^r period. In thus 
reducing the periods of the organic history of the earth, and 
the neptunic strata containing petrifactions deposited during 
those periods, into a connected system, we proceed exactly 


like the historian who divides the history of nations into 
the three main divisions of Antiquity, the Middle Ages, and 
Modern Times, and each of sections again into subordi- 
nate periods and epochs. But the historian by this sharp 
systematic division, and by fixing the boundary of the 
periods by particular dates, only seeks to facilitate his 
survey, and in no way means to deny the uninteiTupted 
connection of events and the development of nations. 
Exactly the same qualification applies to our systematic 
division, specification, or classification of the organic history 
of the earth. Here, too, a continuous thread runs through 
the series of events unbroken We must therefore dis- 
tinctly protest against the idea that by sharply bounding 
the larger and smaller groups of strata, and the periods 
corresponding with them, we in any way wish to adopt 
Cuvier's doctrine of terrestrial revolutions, and of repeated 
new creations of organic populations. That this erroneous 
doctrine has long since been completely refuted by Lyell, I 
have ah-cady mentioned. (Com^Jare vol. i. p. 127.) 

The five great main divisions of the organic history of 
the earth, or the palceontological history of development, 
we call the primordial, primary, secondary, tertiary, and 
quaternary epochs. Each is distinctly characterized by the 
predominating development of certain animal and vegetable 
groups in it, and wo might accordingly symbolically desig- 
nate the five epochs, on the one hand by the names of the 
groups of the vegetable kingdom, and on the other hand by 
those of the difierent classes of vertebrate animals. In this 
case the first, or primordial epoch, would be the era of the 
Tangles (Algaj) and skull-less Vertebrates; the second, or 
primary epoch, that of the Ferns and Fishes ; tne third, or 


secondary epoch, that of Pine Forests and Reptiles; the 
fourth, or tertiary epoch, that of Foliaceous Forests and of 
Mammals ; finally, the fifth, or quaternary epoch, the era 
of Man and his Civilization. The diyisions or periods 
which we distinguish in each of the five long eras 
(p. 14) are determined by the different systems of strata 
into which each of the five great roch-groups is divided 
(p. 15). We shall now take a cursory glance at the series of 
these systems, and at the same time at the po].ulations of 
the five great epochs. 

The first and longest division of the organic history of the 
earth is formed by the primordial epoch, or the era of the 
Tangle Forests. It comprises the immense period from the 
first spontaneous generation, from the origin of the first ter- 
restrial organism, to the end of the Silurian system of 
deposits. During this immeasurable space of time, which in 
all probability was much longer than all the other four 
epochs taken together, the three most extensive of all the 
neptunlc systems of strata were deposited, namely, the 
Laurentian, upon that the Cambrian, and upon that the 
Silurian system. The approximate thickness or size of these 
three systems together amounts to 70,000 feet. Of these 
about 30,000 belong to the Laurentian, 18,000 to the Cam- 
brian, and 22,000 to the Silurian system. The average 
thickness of all the four other rock groups, the primary, 
secondary, tertiary, and quaternary, taken together, may 
amount at most to 60,000 feet; and from this fact alone, 
apart from many other reasons, it is evident that the 
duration of the primordial period was probably much longer 
than the duration of all the subsequent periods down to the 
present day. Many thousands of millions of years were re- 


quired to deposit such masses of strata. Unfortunately, by 
far the largest portion of the primordial group of strata is 
in the metamorphie state (which we shall directly explain), 
and consequently the petrifactions contained in them — the 
most ancient and most important of all — have, to a great 
extent, been destroyed and become unrecognizable. Only in 
one portion of the Cambrian and Silurian strata have petri- 
factions been preserved in a recognizable condition and in 
large quantities. The most ancient of aU distinctly pre- 
served petrifactions has been found in the lowest Lauren- 
tian strata (iu the Ottawa formation), which I shall after- 
wards have to speak of as the " Canadian Life's-dawn " 
(Eozoon canadense). 

Although only by far the smaller portion of the primor- 
dial or archilithic petrifactions are preserved to us in a 
recognizable condition, still they possess the value of inestim- 
able documents of the most ancient and obscure times of the 
organic history of the earth. What seems to be shown by 
them, in the first place, is that during the whole of this im- 
mense period there existed only inliabitants of the waters. 
As yet, at any rate, among all archilithic petrifactions, not 
a single one has been found which can with certainty be 
regarded as an organism which has lived on land. All the 
vegetable remains we possess of the primordial period 
belong to the lowest of all groups of plants, to the class of 
Tangles or Alga), hving in water. In the warm primaeval 
sea, these constituted the forests of the primordial period, 
of the richness of which in forms and density we may form 
an approximate idea from their present descendants, the 
tangle forests of the Atlantic Sargasso sea. The colossal 
tangle forests of the archilithic period supplied the place of 


the forest vegetation of the mainland, which was then 
utterly wanting. All the animals, also, whose remains have 
been found in archilithie strata, like the plants, lived in 
water. Only Crustacea are met with among the animals 
with articulated feet, as yet no spiders and no insects. Of 
vertebrate animals, only a very few remains of fishes are 
known as having been found in the most recent of all 
primordial strata, in the upper Silurian. But the headless 
vertebrate animals, which we call slcull-less, or Acrania, and 
out of which fishes must have been developed, we suppose 
to have lived in great numbers during the primordial epoch. 
Hence we may call it after the Acrania as well as after the 

The priTnary epoch, or the era of Fern Forests, the second 
main division of the organic history of the earth, which is 
also called the palseoUthic or palaeozoic period, lasted from 
the end of the Silurian foimation of strata to the end of the 
Permian formation. This epoch was also of very long dura- 
tion, and again falls into three shorter periods, during whicji 
three great systems of strata were deposited, namely, first, 
the Devonian system, or the old red sandstone ; upon that, 
the Carboniferous, or coal system ; and upon this, the 
Permian system. The average thickness of these three 
systems taken together may amount to about 42,000 feet, 
from which we may infer the immense length of time 
requisite for their formation. 

The Devonian and Permian formations are especially rich 
in remains of fishes, of prunseval fish as well as enamelled 
fish (Ganoids), but the bony fish (Teleostei) are absent from 
the strata of the primary epoch. In coal are found the 
most ancient remains of animals living on land, both of arti- 


Ciliated animals (spiders and insects) as -well as of vertebrate 
animals (amphibious animals, like newts and frogs). In the 
Permian system there occur, in addition to the amphibious 
animals, the more highly-developed reptUes, and, indeed, 
forms nearly related to our lizards (Proterosaurus, etc.). But, 
nevertheless, we may call the primary epoch that of Fishes, 
because these few amphibious animals and reptiles are 
insignificant in comparison with the immense mass of 
palaeozoic fishes. Just as Fishes predominate over the other 
vertebrate animals, so Ferns, or Filices, pi'edominate among 
the plants of this epoch, and, in fact, real ferns and ti^ee ferns 
(leafed ferns, or Phyloptcridso), as well as bamboo ferns 
(Calamophytas) and scaled ferns (Lepidophytas). These 
ferns, which grew on land, formed the chief part of the 
dense palaeolithic island forests, the fossil remains of which 
are preserved to us in the enormously large strata of coal of 
the Carboniferous system, and in the smaller strata of coal of 
the Devonian and Permian systems. . We are thus justified 
in calling the primary epoch either the era of Ferns or that 
of Fishes. 

The third great division of the palseontological history 
of development is formed by the secondary epoch, or the 
era of Pine Forests, which is also called the mesolithic or 
mesozoic epoch. It extends from the end of the Permian 
system to the end of the Chalk formation, and is again 
divided into three great periods. The stratified systems de- 
posited during this period are, first and lowest, the Triassic 
system, in the middle the Jura system, and at the top the 
Cretaceous system. The average thickness of these three 
systems taken together is much less than that of the pri- 
mary group, and amounts as a whole only to about 15,000 


feet. The secondary epoch, can accordingly in all prob- 
ability not have been half so long as the primary epoch. 

Just as Fishes prevailed in the primary epoch, Reptiles 
predominated in the secondary epoch over all other verte- 
brate animals. It is true that during this period the first 
birds and mammals originated ; at that time, also, there 
existed important amphibious animals, especially the gigan- 
tic Labyrinthodonts, in the sea the wonderful sea-dragons, 
or Halisaurii, swam about, and the first fish with bones were 
associated with the many primaeval fishes (Sharks) and 
enamelled fish (Ganoids) of the earlier times ; but the very 
variously developed kinds of reptiles formed the predomi- 
nating and characteristic class of vertebrate animals of the 
secondary epoch. Besides those reptiles which were very 
nearly related to the present living lizards, crocodiles, and 
tui'tles, there were, during the mesolithic period, swarms of 
grotesquely shaped dragons. The remarkable flying lizards, 
or Pterosaurii, and the colossal land-dragons, or Dinosaurii, 
of the secondary epoch, arc peculiar, as they occur neither 
in the preceding nor in the succeeding epochs. The secondary 
epoch may be called the era of Reptiles ; but on the other 
hand, it may also be called the era of Pine Forests, or more 
accurately, of the Gymmospervis, that is, the epoch of plants 
having naked seeds. For this group of plants, especially as 
represented by the two important classes — the pines, or 
Coniferai, and the palm-ferns, or Cycadece — -during the 
secondary epoch constituted a predominant part of the 
forests. But towards the end of the epoch (in the Chalk 
period) the plants of the pine tribe gave place to the leaf- 
bearing forests which then developed for the first time. 

The fourth main division of the organic history of the 



Of the FalcBontoloc/ical Periods, or of the Greater Divisions of the 
Organic History of the Earth. 

I. First Epoch : Aechilithic Era. Primordial Epoch. 

(Era of Sknil.less Animals and Forests of Tangles.) 

1. Older Primordial Period or Lanrentian Period. 

2. Middle Primordial Period „ Cambrian Period. 

3. Later Primordial Period „ SUnrian Period. 

II. Second Epoch : Paleolithic Eka. Primary Epoch. 

(Era of Fish and Fern Forests.) 

4. Older Primary Period or Devonian Period. 

5. Mid Primary Period „ Coal Period. 

6. Later Primary Period „ Permian Period, 

III. Third Epoch : Mesolithic Era. Se-condary Epoch. 

(Era of Reptiles and Pine Forests.) 

7. Older Secondary Period or Trias Period. 

8. Middle Secondary Period „ Jnra Period. 

9. Later Secondary Period „ Chalk Period. 

rV. Fourth Epoch : C^nolithic Eka. Tertiary Epoch, 
(Era of Mammals and Leaf Forests.) 

10. Older Tertiary Period or Eocene Period. 

11. Newer Tertiary Period „ Miocene Period. 

1 2. Eecent Tertiary Period „ Pliocene Period. 

V. Fifth Epoch : Antheoi'olithic Era. Quaternary Epoch. 
(Era of Man and Cultivated Forests.) 

13. Older Qnatemary Period or Ice or Glacial Period. 

14. Newer Qnatemary Period „ Post Glacial Period. 

15. Eecent Quaternary Period „ Period of Cnltnre. 

(The Period of Cnltnre is the Ilistorical Period, or the Period of Tradition.) 



Of the PalcBontological Formations, or those Strata of the Earth's 
Crust containing Petrifactions. 



Formations. Synonyms oj 


Y. Qvaternary 
groups of strata 

IV. Tertiary 





groups of strata \ 

III. Secondary 





p.'Oups of strata [ 

XIV. Eeccnt < 

(AUnvinm) " 

XIII. Pleistocene ' 

(Dilavium) ( 

XII. Pliocene 

(Late tertiary) 

XI. Miocene 

(New tertiary) 

X. Eocene 
(Old tertiary) 

IX. Cretaceous 

VIII. Jura 

VII. Trias 

II. rrimary 





groups of strata / 

I. Primordial 





groups of strata \ 

/ VI. Permian 

V. Carbonic 

IV. Devonian 
(Old red sand- 

III. Silurian 

II. Cambrian 
I. Laurentian 

36. Present 
35. Recent 
34. Post glacial 
33. Glacial 

32. Arvernian 

31. Sui-Appenine 

30. Falunian 

29. TAmburgian 
28. Gypsum 

27. Nwm.mulitic 

26. London day 

25. White chalh 

24. Oreen sand 
23. Neocoviian 

22. Wealden 

21. Portlandian 

20. Oxfordian 

19. Bath 

18. Lias 

17. Keuper 

16. Muschelkalk 

15. Bunter sand 

14. Zeclistein 


12. Cc -honiferous 


11. Carboniferous 


10. Pilton 

9. Iljracomhe 

8. Linton 

7. Idtdloio 

6. Llandovery 

5. LlundrAlo 

4. Potsdam 

3. LoTigmynd 

2. Labrador 

1. Ottawa 

Upper alluvial 
Lower alluvial 
Upper dilavial 
Lower diluvial 

Upper pliocene 
Lower pliocene 
Upper miocene 
Lower miocene 
Upper eocene 
Mid eocene 
Lower eocene 

Upper cretaceous 
Mid cretaceous 
Lower cretaceous 
The Kentish Weald 
Upper oolite 
Mid oolite 
Lower oolite 
Lias formation 
Upper trias 
Mid trias 
Lower trias 

Upper Permian 
Lower Permian 

Upper carbonic 

Lower carbonic 
Upper Devonian 
Mid Devonian 
Lower Devonian 

Upper Silurian 
Mid Silurian 
Lower Silurian 
Upper Cambrian 
Lower Cambrian 
Upper Laurentian 
Lower Laurentiafl 


earth, the tertiary epoch, or era of Leafed Forests, is much 
shorter and less peculiar than the three first epochs. This 
epoch, which is also called the csenolithic or c^nozoic 
epoch, extended from the end of the cretaceous system to 
the end of the pliocene system. The strata deposited 
during it amount only to a thickness of about 3000 feet, and 
consequently are much inferior to the three first great 
groups. The three systems also into "which the tertiary 
period is subdivided are very difficult to distinguish from 
one another. The oldest of them is called eocene, or old 
tertiary; the newer rroiocene, or mid tertiary; and the last 
is the pliocene, or later tertiary system. 

The whole population of the tertiary epoch approaches 
much nearer, on the whole as well as in. detail, to that of 
the present time than is the case in the preceding epochs. 
From this time the class of Mainmals greatly predominates 
over all other vertebrate animals. In like manner, in the 
vegetable kingdom, the group — so rich in forms — of the 
Angiosperms, or plants with covered seeds, predominates, 
and its leafy forests constitute the characteristic feature 
of the tertiary epoch. The group of the Angiosperms con- 
sists of the two classes of single-seed-lobed plants, or Mono- 
cotyledons, and the double-seed-lobed plants, or Dicotyledons. 
The Angiosperms of both classes had, it is trvie, made their 
appearance in the Cretaceous period, and mammals had 
already occurred in the Jurassic period, and even in the 
Triassic period ; but both groups, the mammals and the 
plants with enclosed seeds, did not attain their peculiar 
development and supremacy until the tertiary epoch, so 
that it may justly be called after them. 

The fifth and last main division of the organic histoiy 


of the earth is the quaternary epoch, or era of Civilization, 
which in comparison with the length of the four other 
epochs almost vanishes into nothing, though with a comi- 
cal conceit we usually call its record the " history of the 
worli" As the period is characterized by the development of 
Man and his Culture, which has influenced the organic world 
more powerfully and with greater transforming effect than 
have all previous conditions, it may also be called the era 
of Man, the anthropolithic or anthropozoie period. It might 
also be called the era of Cultivated Forests, or Gardens, 
because even at the lowest stage of human civiUzation 
man's influence is already perceptible in the utilization of 
forests and their products, and therefore also in the 
physiognomy of the landscape. The commencement of 
this era, which extends down to the present time, is 
geologically bounded by the end of the pliocene stratifica- 

The neptunic strata which have been deposited during 
. the comparatively short quaternary epoch are very different 
in different parts of the earth, but they are mostly of very 
slight thickness. They are reduced to two "systems," the 
older of which is designated the diluvial, or pleistocene, 
and the later the alluvial, or recent. The diluvial system 
is again divided into two " formations," the older glacial and 
the more recent fost glacial formations. For during tlie 
older diluvial period there occurred that extremely remark- 
able decrease of the temperature of the earth which led to 
an extensive glaciation of the temperate zones. The great 
importance which this " ice " or " glacial period " has exer- 
cised on the geographical and topographical distribution of 
organisms has akeady been esplaiued in the preceding chap- 


ter (vol. i. p. 365). But the post glacial period, or tlie more 
recent diluvial period, during wliich the temperature again 
increased and the ice retreated towards the poles, was 
also highly important in regard to the present state of 
chorological relations. 

The biological characteristic of the quaternary epoch lies 
essentially in the development and dispersion of the human 
organism and his culture. Man has acted with a greater 
transforming, destructive, and modifying influence upon the 
animal and vegetable population of the earth than any other 
organism. F^or this reason, and not because we assign to man 
a privileged exceptional position in nature in other matters, 
we may with full justice designate the development of man 
and his civilization as the beginning of a special and last 
main division of the organic history of the earth. It is 
probable indeed that the corporeal development of primjeval 
man out of man-like apes took place as far back as the earlier 
pliocene period, perhaps even in the miocene tertiary period. 
But the actual development of human s'peech, which we look 
upon as the most powerful agency in the development of the 
peculiar characteristics of man and his dominion over other 
organisms, probably belongs to that period which on 
geological grounds is distinguished from the preceding 
pliocene period as the pleistocene or diluvial. In fact the 
time which has elapsed from 'the development of human 
speech down to the present day, though it may comprise 
many thousands and perhaps hundreds of thousands of years, 
almost vanishes into nothing as compared with the im- 
measurable length of the periods which have passed from 
the beginning of organic life on the earth down to the 
origin of the human race. 


The tabular view given on page 15 shows the succession 
of the palseontological rock-groups, systems, and formations, 
that is, the larger and smaller neptunic groups of strata, 
which contain petrifactions, from the uppermost, or Alluvial, 
down to the lowest, or Laurentian, deposits. The table on 
page 14 presents the historical division of the correspond- 
ing- eras of the larger and smaller palEeontological periods, 
and in a reversed succession, from the most ancient Lauren- 
tian up to the most recent Quaternary period. 

Many attempts have been made to make an approximate 
calculation of the number of thousands of years constituting 
these periods. The thickness of the strata has been compared, 
which, according to experience, is deposited during a century, 
and which amounts only to some few lines or inches, with 
the whole thickness of the stratified masses of rock, the 
succession of which we have just surveyed. This thickness, 
on the whole, may on an average amount to about 130,000 
feet; of these 70,000 belong to the primordial, or arcliilithic ; 
42,000 to the primary, or palaeolithic; 15,000 to the secondary, 
or mesolithic ; and finally only 3,000 to the tertiary, or 
caenolithic group. The very small and scarcely appreciable 
thickness of the quaternary, or anthropolithic deposit 
cannot here come into consideration at all. On an average, 
it may at most be computed as from 500 to 700 feet. 
But it is self evident that all these measurements have only 
an average and approximate value, and are meant to give 
only a rough survey of the relative proportion of the 
systems of strata and of the spaces of time corresponding 
with them. 

Now, if we divide the whole period of the organic history 
of the earth — that is, from the beginning of life on the earth 

3 . . 

. 53.6 


. 32.1 

• • 

. 11.5 


. 2.3 


. 0.5 


... 100.0 


down to the present day — into a hundred equal parts, and If 
then, corresponding to the thickness of the systems of 
strata, we calculate the relative duration of the time of the 
five main divisions or periods according to percentages, we 
obtain the following result : — 

I. ArcBilltliic, or primordial period 

II. Palseolithic, or primary period . 

III. llesolithic, or secondary period 

IV. CaBnolithio, or tertiary period 
V. Anthropolithio, or quaternary period 

According to this, the length of the archilithic period, 
during which no land-living animals or plants as yet existed, 
amounts to more than one half, more than 53 per cent. ; on the 
other hand the length of the anthropolithic era, during which 
man has existed, amounts to scarcely one-half per cent, of 
the whole length of the organic history of the earth. It is, 
however, quite impossible to calculate the length of these 
periods, even approximately, by years. 

The thickness of the strata of mud at present deposited 
during a century, and which has been used as a basis for 
this calculation, is of course quite different in different parts 
of the earth under the different conditions in which these 
deposits take place. It is very slight at the bottom of the 
deep sea, in the beds of broad rivers with a short course, and 
in inland seas which receive very scanty supplies of water. 
It is comparatively gi'eat on the sea-shores exposed to strong 
breakers, at the estuaries of large rivers with long courses, 
and in inland seas with copious supplies of water. At the 
mouth of the Mississippi, which carries with it a consider- 


able amourt of mud, in the course of 100,000 years about 
600 feet would be deposited. At the bottom of the open 
sea, far away from the coasts, during this long period onljr 
some few feet of m.ud would be deposited. Even on the 
sea-shores where a comparatively large quantity of mud is 
deposited the thickness of the strata formed during the 
course of a century may after all amount to no more than 
a few inches or lines when condensed into solid stone. In 
any case, however, all calculations based upon these com- 
parisons are very unsafe, and we cannot even approximately 
conceive tlie enormous length of the periods which were 
requisite for the formation of the systems of neptunic 
strata. Here we can apply only relative, not absolute, 
measurements of time. 

Moreover, we should entirely err were we to consider the 
size of these systems of strata alone as the measure of the 
actual space of time which has elapsed during the earth's 
history. For the elevations and depressions of the earth's 
crust have perpetually alternated with one another, and the 
mineralogical and paliBontological difference — which is per- 
ceived between each two succeeding systems of strata, and 
between each two of their formations at any particular spot — 
corresponds in all probability with a considerable intermedi- 
ate space of many thousands of j'ears, during which that 
particular part of the earth's crust vs^as raised above the 
water. It was only after the lapse of this intermediate 
period, when a new depression again laid the part in ques- 
tion under water, that there occurred a new deposit of 
earth. As, in the mean time, the inorganic and organic con- 
ditions on this part had undergone a considerable transform- 
ation, the newly-formed layer of mud was necessarily com- 



IV. Tertiary Group of 
Strata, 3000 feet. 

Eocene, Miocene, Pliocene. 


Mcsolitliic Group of Strata. 
Deposits of the 
Secondary Epoch, abont 
15,000 feet. 

IX. Chalk System. 

VIII. Jni-a System. 

VII. Trias System. 


FaloDolithic Group of Strata. 

Deposits of tho 

Primarj' Epoch, about 

42,000 feet. 

VI. Permian Sj^stem. 

V. Coal System. 

IV. Devonian System, 


Archilithic Group of Strata. 

Deposits of the 

Primordial Epoch, about 

70,000 feet. 

III. Siluiian System, about 
• 22,000 feet. 

II. Cambrian System, abont 
1S,000 feet. 

I. Laurentian System, abont 
30,000 feet. 


posed of different earthy constituents and enclosed different 

The striking differences which so frequently occur be- 
tween the petrifactions of two strata, lying one above 
another, are to be explained in a simple and easy manner, by 
the supposition that the same part of the earth's surface has 
been exposed to repeated depressions and elevations. Such 
alternating elevations and depi-essions take place even now 
extensively, and are ascribed to the heaving of the fiery 
fluid nucleus against the rigid crust. Thus, for example, 
the coast of Sweden and a portion of the west coast of 
South America are constantly though slowly rising, while 
the coast of Holland and a portion of the east coast of 
South America are gradually sinking. The rising as weU as 
the sinking takes place very slowly, and in the course of a 
century sometimes only amounts to some few lines, some- 
times to a few inches, or at most a few feet. But if this 
action continues uninterruptedly throughout hundreds of 
thousands of years it is capable of forming the highest 

It is evident that elevations and depressions, such as 
now can be measured in these places, have uninterruptedly 
alternated one with another in different places during the 
whole course of the organic history of the earth. This 
may be inferred with certainty from the geographical distri- 
bution of organisms. (Compare vol. i. p. 350.) But to form a 
judgment of our palseontological records of creation it is ex- 
tremely important to show that permanent strata can only 
be deposited during a slow sinking of the ground under 
water, but not during its continued rising. When the 
ground slowly sinks more and more below the level of the 


sea, the deposited layers of mud get into continually deeper 
and quieter water, where they can become condensed into 
stone undisturbed. But when, on the other hand, the 
ground slowly rises, the newly-deposited layers of mud, 
which enclose the remains of plants and animals, again im- 
mediately come within the reach of the play of the waves, 
and are soon worn away by the force of the breakers, 
together with the organic remains which they enclose. For 
this simple but very important reason, therefore, abundant 
layers, in which organic remains are preserved, can only 
be deposited during a continuous sinking of the ground. 
When any two different formations or strata, lying one 
above the other, correspond with two different periods of de- 
pression, we must assume a long peiiod of rising between 
them, of which period we know nothing, because no fossil 
remains of the then living animals and plants could be pre- 
seiwed. It is evident, however, that these periods oj 
elevation, which have passed without leaving any trace be- 
hind them, deserve a no less careful consideration than the 
greater or less alternating periods of depression, of whose 
organic population we can form an approximate idea from 
the strata containing petrifactions. Probably the former 
were not of shorter duration than the latter. 

From this alone it is apparent how imperfect our records 
must necessarily be, and all the more so since it can 
be theoretically proved that the variety of animal and 
vegetable life must have increased greatly during those very 
periods of elevation. For as new tracts of land are raised 
above the water, new islands are formed. Every new 
island, however, is a new centre of creation, because the 
animals and plants accidentally cast ashore there, find in 


the new territory, in the struggle for life, abundant oppor- 
tunity of developing themselves peculiarly, and of forming 
new species. This formation of new species has evidently 
taken place pre-eminently during these intermediate 
periods, of which, unfortunately, no petrifactions could 
be preserved, whereas, on the contrary, during the slow 
sinking of the ground there was more chance of nume- 
rous species dying out, and of a retrogression into 
fewer specific forms. The intermediate forms between the 
old and the newly-forming species must also have lived 
during the periods of elevation, and consequently could 
likewise leave no fossil remains. 

In addition to the great and deplorable gaps in the palaj- 
ontological records of creation — which are caused by the 
periods of elevation — there are, unfortunately, many other 
circumstances which immensely diminish their value. I 
must mention here especially the metamoiyJiic state of the 
most ancient formations, of those strata which contain the 
remains of the most ancient flora and fauna, the original 
forms of all subsequent organisms, and which, therefore, 
would be of especial interest. It is just these rocks — and, 
indeed, the greater part of the primordial, or archilithic 
strata, almost the whole of the Laurentian, and a large part 
of the Cambrian systems — which no longer contain any 
recognizable remains, and for the simple reason that these 
strata have been subsequently changed or metamorphosed 
by the influence of the fiery fluid interior of the earth. 
These deepest neptunic strata of the crust have been com- 
pletely changed from their original condition by the heat 
of the glowing nucleus of the earth, and have assumed 
a crystalline state. In this process, however, the form of 


the organic remains enclosed in them has been entirely 
destroyed. It has been preserved only here and there by a 
happy chance, as in the case of the most ancient petrifac- 
tions known, the Eozoon canadense, from the lowest 
Laurentian strata. However, from the layers of crystallino 
charcoal (graphite) and crystalline limestone (marble), 
■which are found deposited in the metamorphic rocks, we 
may with certainty conclude that petrified animal and 
vegetable remains existed in them in earlier times. 

Our record of creation is also extremely imperfect from the 
circumstance that only a small portion of the earth's sur- 
face has been atcurately investigated by geologists, namely, 
England, Germany, and France. But we know very little 
of the other parts of Europe, of Russia, Spain, Italy, and 
Turkey. In the whole of Europe, only some few parts of the 
earth's crust have been laid open, by far the largest portion of 
it is unknown to us. The same applies to North America and 
to the East Indies. There some few tracts have been investi- 
gated ; but of the larger portion of Asia, the most extensive 
of all continents, we know almost nothing ; of Africa almost 
nothing, excepting the Cape of Good Hope and the shores of 
the Mediterranean; of Australia almost nothing; and of South 
America but very little. It is clear, therefore, that only quite 
a small portion, perhaps scarcely the thousandth part of the 
whole surface of the earth, has been palaeontologically 
investigated. We may therefore reasonably hope, when 
more extensive geological investigations are made, which 
are greatly assisted by the constructions of raikoads and 
mines, to find a great number of other important petrifac- 
tions. A hint that this wiU be the case is given by the 
remarkable petrifactions found in those parts of Africa and 


Asia which have been minutely investigated,^the Cape 
districts and the Himalaya mountains. A series of entirely 
new and very peculiar animal forms have become known to 
us from the rocks of these localities. But we must bear in 
mind that the vast bottom of the existing oceans is at the 
present time quite inaccessible to palseontological investiga- 
tions, and that the greater part of the petrifactions which 
have lain there from primaeval times will either never be 
known to us, or at best only after the course of many 
thousands of years, when the present bottom of the ocean 
shall have become accessible by gradual elevation. If we 
call to mind the fact that three-fifths of the whole surface 
of the earth consists of water, and only two-fifths of land, 
it becomes plain that on this account the palajontological 
record must always present an immense gap. 

But, in addition to these, there exists another series of 
difficulties in the way of paleontology which arises from 
the nature of the organisms themselves. In the first place, 
as a rule only the hard and solid parts of organisms can fall 
to the bottom of the sea or of fresh waters, and be there 
enclosed in the mud and petrified. Hence it is only 
the bones and teeth of vertebrate animals, the calcareous 
shells of moUuscs, the chitinous skeletons of articulated 
animals, the calcareous skeletons of star-fishes and corals, 
and the woody and solid parts of plants, that are capable 
of being petrified. But soft and delicate parts, which 
constitute by far the greater portion of the bodies of most 
organisms, are very rarely deposited in the mud under cir- 
cumstances favourable to their becoming petrified, or dis- 
tinctly imjDrcssing their external form upon the hardening 
mud. Now, it must be borne in mind that large classes of 


organisms, as for example the Medusas, tKe naked molluscs 
without shells, a large portion of the articulated animals, 
almost aU worms, and even the lowest vertebrate animals, 
possess no firm and hard parts capable of being petrified. In 
like manner the most important parts of plants, such as the 
flowers, are for the most part so soft and tender that they 
cannot be preserved in a recognizable form. We therefore 
cannot expect to find any petrified remains of these import- 
ant organisms. Moreover, aU organisms at an early stage of 
life are so soft and tender that they are quite incapable of 
being petrified. Consequently all the petrifactions found in 
the neptunic stratifications of the earth's crust comprise 
altogether but a very few forms, and of these for the most 
part only isolated fragments. 

We must next bear in mind that the dead bodies of the 
inhabitants of the sea are much more likely to be preserved 
and petrified in the deposits of mud than those of the in- 
habitants of fresh water and of the land. Organisms living 
on land can, as a rule, become petrified only when their 
coi-pses fall accidentally into the water and are buried at the 
bottom in the hardening layers of mud. But this event 
depends upon very many conditions. We cannot therefore 
be astonished that by far the majority of petrifactions belong 
to organisms which have Lived in the sea, and that of the 
inhabitants of the land proportionately only very few are 
preserved in a fossil state. How many contingencies come 
into play here we may infer from the single fact that of 
many fossil mammals, in fact of all the mammals of the 
secondary, or mesozoic epoch, nothing is known excepf, 
the lower jawbone. This bone is in the first place com- 
paratively solid, and in the second place very easily separates 


itself from tlie dead body, which floats on the -water. Whilst 
the body is driven away and dissolved by the water, the 
lower jawbone falls down to the bottom of the water and is 
there enclosed in the mud. This explains the remark- 
able fact that in a stratum of limestone of the Jurassic 
system near Oxford, in the slates of Stonesfield, as yet only 
the lower jawbones of numerous pouched animals (Mar- 
supials) have been found. They are the most ancient 
mammals known, and of the whole of the rest of their bodies 
not a single bone exists. The opponents of the theory of 
development, according to their usual logic, would from this 
fact be obliged to draw the conclusion that the lower jaw- 
bone was the only bone in the body of those animals. 

Footprints are very instructive when we attempt to 
estimate the many accidents which so arbitrarily influence 
our knowledge of fossils ; they are found in great numbers 
in different extensive layers of sandstone ; for example, in 
the red sandstone of Connecticut, in North America. These 
footprints were evidently made by vertebrate animals, 
probably by reptiles, of whose bodies not the slightest trace 
has been preserved.* The impressions which their feet 
have left on the mud alone betray the former existence of 
these otherwise unknown animals. 

The accidents which, besides these, determine the limits 
of our palseontological knowledge, may be inferred from 
the fact that we know of only one or two specimens of very 
many important petrifactions. It is not ten years since we 
became acquainted with the imperfect impression of a bird 
in the Jurassic or Oolitic system, the knowledge of which 

* With the exception of a single apecimen of the bones of a foot, preserred 
in the cabinet of Amherst College. — E. E. L. 


has been of the very greatest importance for the phylogeny 
of the whole class of birds. All birds previously known 
presented a very uniformly organized group, and showed no 
striking transitional forms to other vertebrate classes, not 
even to the nearly related reptiles. But that fossil bird 
from the Jura possessed not an ordinary bird's tail, but a 
lizard's tail, and thus confirmed what had been conjectured 
upon other grounds, namely, the derivation of birds from 
lizards. This single fossil has thus essentially extended not 
only our knowledge of the age of the class of birds, but also 
of their blood relationship to reptiles. In like manner our 
knowledge of other animal gToups has been often essentially 
modified by the accidental discovery of a single fossil. The 
palfEontological records must necessarily be exceedingly im- 
perfect, because we know of so very few examples, or only 
mere fragments of very many important fossils. 

Another and very sensible gap in these records is caused 
by the circumstance that the intei-mediate forms which xon- 
nect the different species have, as a rule, not been preserved, 
and for the simple reason that (according to the princij)le of 
divergence of character) they were less favoured in the 
struggle for life than the most divergent varieties, which 
had developed out of one and the same original form. The 
intermediate links have, on the whole, always died out 
rapidly, and have but rarely been preserved as fossils. On 
the other hand, the most divergent forms were able to main- 
tain themselves in life for a longer period as independent 
species, to propagate more numerously, and consequently to 
be more readily petrified. But this does not exclude the 
fact that in some cases the connecting intermediate forms 
of the species have been i^reserved so perfectly petrified, that 


even no-w they cause the greatest perplexity and occasion 
endless disputes among systematic palaeontologists about the 
arbitrary limits of species. 

An excellent example of this is furnished by the celebrated 
and very variable fresh-water snail from the Stuben Valley, 
near Steinheim, in Wurtemburg, which has been described 
sometimes as Paludina, sometimes as Fafeata,and sometimes 
as Planorbis multiformis. The snow-white shells of these 
small snails constitute more than half of the mass of the 
tertiary limestone hills, and in this one locality show such an 
astonishing variety of forms, that the most divergent extremes 
might be referred to at least twenty entirely different species. 
But all these extreme forms are united by such innumerable 
intermediate forms, and they lie so regularly above and 
beside one another, that Hilgendorf was able, in the clearest 
manner, to unravel the pedigree of the whole group of 
forms. In like manner, among very many other fossil 
species (for example, many ammonites,- terebratulte, sea 
urchins, lily encrinites, etc.) there are such masses of con- 
necting intermediate forms, that they reduce the " dealers 
in fossil species " to despair. 

When we weigh all the circumstances here mentioned, 
the number of which might easily be increased, it does 
not appear astonishing that the natural accounts or 
records of creation formed by petrifactions are extremely 
defective and incomplete. But nevertheless, the petrifactions 
actually discovered are of the greatest value. Their signifi- 
cance is of no less importance to the natural history of 
creation than the celebrated inscription on the Rosetta 
stone, and the decree of Canopus, are to the history of 
nations — to archaeology and philology. Just as it has 


become possible by means of these two most ancient in- 
scriptions to reconstruct the history of ancient Egypt, and 
to decipher all hieroglyphic writings, so in many cases a few 
bones of an animal, or imperfect impressions of a lower 
animal or vegetable fonn, are sufficient for us to gain the 
most important starting-points in the history of the whole 
group, and in the search after their pedigree. A couple of 
small back teeth, which have been found in the Keuper 
formation of the Trias, have of themselves alone furnished 
a sure proof that mammals existed even in the Triassic 

Of the incompleteness of the geological accounts of 
creation, Darwin, agreeing with LyeU, the greatest of all 
recent geologists, says :— 

" I look at the geological record as a history of the world 
imperfectly kept, and written in a changing dialect ; of this 
history we possess the last volume alone, relating only to 
two or three countries. Of this volume, only here and there 
a short chapter has been preserved ; and of each page, only 
here and there a few lines. Each word of the slowly- 
changing language, more or less different in the successive 
chapters, may represent the forms of life which are en- 
tombed in our consecutive formations, and which falsely 
appear to us to have been abruptly introduced. On this 
view, the difliculties above discussed are greatly diminished, 
or even disappear." — Origin of Species, 6th Edition, p. 289. 

If we bear in mind the exceeding incompleteness of 
palseontological records, we shall not be surprised that we 
are still dependent upon so many uncertain hypotheses when 
actually endeavouring to sketch the pedigree of the different 
organic groups. However, we fortunately possess, besides 


fossils, other records of the history of the origin of organ- 
isms, which in many cases are of no less value, nay, in 
several cases are of much greater value, than fossils. By 
far the most important of these other records of creation is, 
without doubt, ontogeny, that is, the history of the develop- 
ment of the organic individual (embryology and metamor- 
phology). It briefly repeats in great and marked features 
the series of forms which the ancestors of the respective 
individuals have passed through from the beginning of their 
tribe. We have designated the palseontological history of 
the development of the ancestors of a living form as the 
history of a tribe, or phytogeny, and we may therefore thus 
enunciate this exceedingly important biogenetic fundamental 
principle: " Ontogeny is a short and quick repetition, or 
recapitulation, of Phylogeny, detertnined by the laws of In- 
heritance and Adaptation." As every animal and every 
plant from the beginning of its individual existence passes 
through a series of different forms, it indicates in rapid 
succession and in general outlines the long and slowly 
changing series of states of form which its progenitors have 
passed through from the most ancient times. (Gen. Morph. 
iL 6, 110, 300.) 

It ia true that the sketch which the ontogeny of or- 
ganisms gives us of their phylogeny is in most cases more 
or less obscured, and all the more so the more Adaptation, 
in the course of time, has predominated over Inheritance, 
and the more powerfully the law of abbreviated inheritance, 
and the law of correlative adaptation, have exerted their 
influence. However, this does not lessen the great value 
which the actual and faithfully preserved features of that 
sketch possess. Ontogeny is of tlie most inestimable value 


for the knowledge of the earliest palceontological conditions 
of development, just because no petrified remains of tlie 
most ancient conditions of the development of tribes and 
classes have been preserved. These, indeed, could not have 
been preserved on account of the soft and tender nature of 
their bodies. No petrifactions could inform us of the funda- 
mental and important fact which ontogeny reveals to us, 
that the most ancient common ancestors of aU the different 
animal and vegetable species were quite simple cells like 
the egg-celL No petrifaction could prove to us the im- 
mensely important fact, established by Ontogeny, that the 
simple increase, the formation of cell-aggregates and the 
differentiation of those cells, produced the infinitely mani- 
fold forms of multicellular organisms. Thus ontogeny helps 
us over many and large gaps in palssontology. 

To the invaluable records of creation furnished by 
paleontology and ontogeny are added the no less important 
evidences for the blood relationship of organisms furnished 
by contiparative anatomy. When organisms, externally 
very difierent, nearly agree in their internal structure, one 
may with certainty conclude that the agreement has its 
foundation in Inheritance, the dissimilarity its foundation 
in Adaptation. Compare, for example, the hands and fore 
paws of the nine difierent animals which are represented 
on Plate IV., in which the bony skeleton in the interior of the 
hand and of the five fingers is visible. Everywhere we find, 
though the external forms are most different, the same bones, 
and among them the same number, position, and connection. 
It will perhaps appear very natural that the hand of mun 
(Fig. 1) differs very Httle from that of the gorilla (Fig. 2) and 
of the orang-outang (Fig. 3), his nearest relations. But it will 

Hand of Nine diflerent M,-^mraHl.s 


1. Mini, 2.(lni-,ll,, . .■■;. Dninq, Llhni. 5. Seal 
(i.Torpoise, 7. PuU, ,H. Moir, il Diir/v -bUL 


be more surprising if the fore feet of the dog also (Fig. 4), 
as well as the breast-fin (the hand) of the seal (Fig. 5), and 
of the dolphin (Fig. 6), show essentially the same structure. 
And it will appear still more wonderful that even the wing 
of the hat (Fig. 7), the shovel-feet of the mole (Fig. 8), and 
the fore feet of the duck-bill (Omithorhynchus) (Fig. 9), the 
most imperfect of all mammals, is composed of entirely 
the same bones, only their size and form being variously 
changed. Their number, the manner of their arrangement 
and connection has remained the same. (Compare also the 
explanation of Plate IV., in the Appendix.) It is quite incon- 
ceivable that any other cause, except the common inheritance 
of the part in question from common ancestors, could have 
occasioned this wonderful homology or similarity in the 
essential inner structure with such different external forms. 
Now, if we go down further in the system below the mam- 
mals, and find that even the wings of birds, the fore feet of 
reptiles and amphibious animals, are composed of essentially 
the same bones as the arms of man and the fore legs of 
the other mammals, we can, from this circumstance alone, 
with perfect certainty, infer the common origin of aU these 
vertebrate animals. Here, as in all other cases, the degree 
of the internal agreement in the form discloses to us the 
degree of blood relationship. 




Special Mode of Carrying out the Theory of Descent in the Natural System 
of Organisms. — Construction of Pedigrees. — Descent of all Many- 
Celled from Single-Celled Organisms. — Descent of Cells from Monera. — 
Meaning of Organic Tribes, or Phyla. — Number of the Tribes in the 
Animal and Vegetable Kingdoms.— The Monophyletic Hypothesis of 
Descent, or the Hypothesis of one Common Progenitor, and the 
Polyphyletio Hypothesis of Descent, or the Hypothesis of Many 
Progenitors. — The Kingdom of Protista, or Primaeval Beings. — Eight 
Classes of the Protista Kingdom — Monera, Amoebse, or Protoplastte. — 
Whip-swimmers, or Flagellata. — Ciliated-balls, or Catallacta. — Labyrinth, 
streamers, or LabyrinthuleEe.— Flint-cells, or DiatomesB. — Mncous-mouldB, 
orMyxomyoetes.— Eoot-footers (Ehizopoda). — Eemarks on the General 
Natural History of the Protista : Their Vital Phenomena, Chemical 
Composition, and Formation (Individuality and Fundamental Form). — 
Phylugeny of the Protista Kingdom. 

Bt a careful comparison of the individual and the palseonto- 
logical development, as also by the comparative anatomy 
of organisms, by the comparative examination of their 
fully developed structural characteristics, we arrive at 
the knowledge of the degrees of their different structural 
relationships. By this, however, Ave at the same time 
obtain an insight into tlieir true blood relationsJiip, which, 
according to tlie Theory of Descent, is the real reason of the 
structural relationship. Hence by collecting, comparing, and 


emplojdng the empirical results of embryology, paljEon- 
tology, and anatomy for supplementing each other, we 
arrive at an approximate knowledge of " the Natural 
System," which, according to our views, is the pedigree of 
organisms. It is true that our human knowledge, in all 
things fragmentary, is especially so in this case, on account 
of the extreme incompleteness and defectiveness of the 
records of creation. However, we must not allow this to 
discourage us, or to deter us from undertaking this highest 
problem of biology. Let us rather see how far it may even 
now be possible, in spite of the imperfect state of our 
embryological, palseontological, and anatomical knovdedge, 
to establish a probable scheme of the genealogical relation- 
ships of organisms. 

Darwin in his book gives us no answer to these special 
questions of the Theory of Descent; at the conclusion he 
only expresses his conjecture "that animals have de- 
scended from at most only four or five progenitors, and plants 
from an equal or less number." But as these few aboriginal 
forms still show traces of relationship, and as the animal 
and vegetable kingdoms are connected by intermediate tran- 
sitional forms, he arrives afterwards at the opinion "that 
probably all the organic beings which have ever lived on 
the earth have descended from some one primordial form, 
into which life was first breathed by the Creator." Like 
Darwin, all other adherents of the Theory of Descent have 
only treated it in a general way, and not made the attempt 
to carry it out specially, and to treat the " Natural System " 
actually as the pedigree of organisms. If, therefore, we 
venture upon this difficult undertaking, we must take up 
independent ground. 


Four years ago I set up a number of hypothetical genea- 
logies for the larger groups of organisms in the systematic 
introduction to my General History of Development (Gen. 
Morph. vol ii.), and thereby, in fact, made the first attempt 
actually to construct the pedigrees of organisms in the 
manner required by the theory of development. I was 
quite conscious of the extreme difficulty of the task, and as 
I undertook it in spite of aU discouraging obstacles, I claim 
no more than the merit of having made the first attempt and 
given a stimulus for other and better attempts. Probably 
most zoologists and botanists were but little satisfied with' 
this beginning, and least so in reference to the special domain 
in which each one is specially at work. However, it is cer- 
tainly in this case much easier to blame than to produce 
something better, and what best proves the immense diffi- 
culty of this infinitely complicated task is the fact that no 
naturalist has as yet supplied the place of my pedigrees by 
better ones. But, like all other scientific hypotheses which 
serve to explain facts, my genealogical hjrpotheses may 
claim to be taken into consideration until they are re- 
placed by better ones. 

I hope that this replacement wiU veiy soon take place ; 
and I wish for nothing- more than that my first attempt 
may induce very many naturalists to establish more accm-ate 
pedigrees for the individual groups, at least in the special 
domain of the animal and vegetable kingdom which 
happens to be well known to one or other of them. By 
numerous attempts of this kind our genealogical know- 
ledge, in the course of time, wiU slowly advance and 
approach more and more towards perfection, although it can 
with certainty be foreseen that we shall never arrive at a 


complete pedigree. We lack, and shall ever lack, the indis- 
pensable palseontological foundations. The most ancient 
records will ever remain sealed to us, for reasons which 
have been previously mentioned. The most ancient organ- 
isms which arose by spontaneous generation — the original 
parents of all subsequent organisms — must necessarily be 
supposed to have been Monera — simple, soft, albuminous 
lumps, without structure, without any definite forms, and 
entirely without any hard and formed parts. They and 
their next offspring were consequently not in any way 
capable of being preserved in a petrified condition. But we 
also lack, for reasons discussed in detail in the preceding 
chapter, by far the greater portion of the innumerable 
palssontological documents, which are really requisite for a 
safe reconstruction of the history of animal tribes, or 
phylogeny, and for the true knowledge of the pedigree of 
organisms. If we, therefore, in spite of this, venture to 
undertake their hypothetical construction, we must chiefly 
depend for guidance on the two other series of records 
which most essentially supplement the palseontological 
archives. These are ontogeny and comparative anatomy. 

If thoughtfully and carefully we consult these most 
valuable records, we at once perceive what is exceedingly 
significant, namely, that by far the gi-eater number of 
organisms, especially all higher animals and plants, are com- 
posed of a great number of cells, and that they originate out 
of an egg, and that this egg, in animals as well as in plants, 
is a single, perfectly simple cell — a little lump of albuminous 
constitution, in which another albuminous corpuscle, 
the cell-kernel, is enclosed. This cell containing its kernel 
grows and becomes eiilarged. By division it forms an 


accumulation of cells, and out of these, by division of 
labour (as has previously been described), there arise 
the numberless different forms which are presented to us 
in the fully developed animal and vegetable species. This 
immensely important process — wliich we may follow step 
by step, with our own eyes, any day in the embryological 
development of any animal or vegetable individual, and 
which as a rule is by no means considered with the 
reverence it deserves— informs us more surely and com- 
pletely than all petrifactions could do as to the original 
palEeontological development of all many-celled organisms, 
that is, of all higher animals and plants. For as ontogeny, 
or the embryological development of every single individual, 
is essentially only a recapitulation of phylogeny, or the 
palseontological development of its chain of ancestors, we 
may at once, with full assurance, draw the simple and 
important conclusion, that all many-celled animals and 
plants were originally derived from single-celled organisms. 
The primreval ancestors of man, as well as of all other 
animals, and of all plants composed of many cells, were simple 
cells bving isolated. This invaluable secret of the organic 
pedigree is revealed to us with infallible certainty by the 
egg of animals, and by the true egg-cell of plants. When the 
opponents of the Theory of Descent assert it to be miraculous 
and inconceivable that an exceedingly complicated many- 
celled organism could, in the course of time, have proceeded 
from a simple single-celled organism, we at once reply that we 
may see this incredible miracle at any moment, and foUow it 
with our own eyes. For the embryology of animals and 
plants visibly presents to our eyes in the shortest space of 
time the same process as that which has taken place in the 


origin of the whole tribe during the course of enormous 
periods of time. 

Upon the ground of embryological records, therefore, we 
can with full assurance maintain that all many-celled, as 
weU as single-celled, organisms are originally descended from 
simple cells ; connected with this, of course, is the conclusion 
that the most ancient root of the animal and vegetable 
kingdom was common to both. For the different primaeval 
" original cells " out of which the few different main groups 
or tribes have developed, only acquired their differences 
after a time, and were descended from a common " primaeval 
cell." But where did those few " original cells," or the one 
primseval cell, come from ? For the answer to this funda- 
mental genealogical question we must return to the theory 
of plastids and the hypothesis of spontaneous generation 
which we have already discussed (vol. i. p. 327). 

As was then shown, we cannot imagine cells to have arisen 

by spontaneous generation, but only Ifomera, those primaeval 

creatures of the simplest kind conceivable, like the still 

living Protamoebse, Protomyxse, etc. (voL i. p. 186, Fig. 1). 

only such corpuscules of mucus without component parts — 

whoso whole albuminous body is as homogeneous in itself as 

an inorganic crystal, but which nevertheless fulfils the two 

organic fundamental functions of nutrition and propagation 

— could have directly arisen out of inorganic matter by auto- 

geny at the beginning (we may suppose) of the Laurentian 

period. While some Monera remained at the original simple 

stage of formation, others gradually developed into cells by 

the inner kernel of the albuminous mass becoming separated 

from the external cell-substance. In others, by differentiation 

of the outermost layer of the cell-substance, an external 


covering (membrane, or skin) was formed round simple cytods 
(without kernel), as weU as round naked cells (containing a 
kernel). By these two processes of separation in the simple 
primaeval mucus of the Moneron body, by the formation of 
a kernel in the interior and a covering on the outer surface 
of the mass of plasma, there arose out of the original most 
simple cytods, or Monera, those four different species of 
plastids, or individuals, of the first order, from which, by 
differentiation and combination, all other organisms c^uld 
afterwards develop themselves. (Compare vol. i. p. 347.) 

The question now forces itself upon us, Are all organic 
cytods and cells, and consequently also those " original cells " 
which we previously considered to be the primary parents of 
the few grekt main groups of the animal and vegetable king- 
doms, descended from a single original form of Moneron, or 
were there several different organic primary forms, each 
traceable to a peculiar independent species of Moneron 
which originated by spontaneous generation ? In other 
words, 7s the luhole organic world of a cowiTnon origin, or 
does it owe its origin to several acts of s'pontaneous genera- 
tion ? This fundamental question of genealogy seems at 
first sight to be of exceeding importance. But on a more 
accurate examination, we shall soon see that this is not 
the case, and that it is in reality a matter of very subor- 
dinate importance. 

Let us now pass on to examine and clearly limit our 
conception of an organic tribe. By tribe, or phylum, we 
understand aU those organisms of whose blood relationship 
and descent from a common primary form there can be no 
doubt, or whose relationship, at least, is most probable from 
anatomical reasons, as well as from reasons founded on his- 


torical development. Our tribes, or pliyla, according to this 
idea, essentially coincide with those few " great classes," or 
" main classes," of whichDarwin also thinks that each contains 
only organisms related by blood, and of which, both in the 
animal and in the vegetable kingdoms, he only assumes either 
four or tive. In the animal kingdom these tribes would essen- 
tially coincide with those four, five, or six main divisions 
which zoologists, since Bar and Cuvier, have distinguished as 
" main forms, general plans, branches, or sub-kingdoms " of 
the animal kingdom. (Compare vol. i. p. 53.) Bar and Cuvier 
distinguished only four of them, namely : — 1. The vertebrate 
animals (Vertebrata) ; 2. The articulated animals (Articulata) ; 
3. The molluscous animals (MoUusca); and 4. The radiated 
animals (Radiata). At present six are generally distinguished, 
since the tribe of the articulated animals is divided into two 
tribes, those possessing articulated feet (Ai-thropoda), and the 
worms (Vermes) ; and iii like manner the tribe of radiated 
animals is subdivided into the two tribes of the star animals 
(Echinodermata) and the animal-plants (Zoophyta). Within 
each of these six tribes, all the included animals, in spite of 
great variety in external form and inner structure, never- 
theless possess such numerous and important characteristics 
in common, that there can be no doubt of their blood 
relationship. The same applies also to the six great main 
classes which modern botany distinguishes in the vegetable 
kingdom, namely : — 1. Flowering plants (Plianerogamia) ; 
2. Ferns (Filicinje) ; 3. Mosses (Muscina;) ; 4. Lichens 
(Lichenes) ; 5. Fungi (Fungi) ; and 6. Water- weeds (Algse). 
The last three groups, again, show such close relations to one 
another, that by the name of " Thallus plants " they may be 
contreisted with the three first main classes, and consequently 


the number of phyla, or main groups, of the vegetabla 
kingdom may be reduced to the number of four. Mosses and 
ferns may likewise be comprised as "Prothallus plants' 
(Prothallophyta), and thereby the number of plant tribes 
reduced to three — Flowering plants, Prothallus plants, and 
Tliallus plants. 

Very important facts in the anatomy and the history 
of development, both in the animal and vegetable king- 
doms, support the supposition that even these few main 
classes or tribes are connected at their roots, that is, that 
the lowest and most ancient primary forms of all three are 
related by blood to one another. Nay, by a fui-ther examin- 
ation we are obliged to go stiU a step further, and to agree 
with Darwin's supposition, that even the two pedigrees of 
the animal and vegetable kingdom are connected at their 
lowest roots, and tliat the lowest and most ancient animals 
and plants are derived from a single common primary 
creature. According to our view, this common primisval 
organism can have been nothino; but a Moneron which took 
its origin by spontaneous generation. 

In the mean time we shall at all events be acting cau- 
tiously if we avoid this last step, and assume true blood 
relationship only within each tribe, or phylum, where it has 
been undeniably and surely established by facts in compara- 
tive anatomy, ontogeny, and phylogeny. But we may here 
point to the fact that two different fundamental forms of 
genealogical hypothesis are possible, and that all the differ- 
ent investigations of the Theory of Descent in relation to the 
origin of organic groups of forms will, in future, tend 
more and more in one or the other of these directions. The 
unitary, or 'nionophyletic, hypothesis of descent will endeavour 


to trace the first origin of all individual groups of organisms, 
as well as their totality, to a single common species of 
Moneron which originated by spontaneous generation (vol. i. 
p. 343). The multiple, or polyphyletic, hypothesis of descent, 
on the other hand, will assume that several, different species 
of Monera have arisen by spontaneous generation, and that 
these gave rise to several different main classes (tribes, or 
phyla) (vol. i. p. 348). The apparently great contrast between 
these two hyf)otheses is in reality of very little importance. 
For both the monophyletic and the polyphyletic hypothesis of 
descent must necessarily go back to the Monera as the most 
ancient root of the one or of the many organic tribes. But 
as the whole body of a Moneron consists only of a simple, 
formless mass, without component particles, made up of a 
single albuminous combination of carbon, it follows that the 
differences of the different Monera can only be of a chemical 
nature, and can only consist in a different atomic com- 
position of that mucous albuminous combination. But 
these subtle and complicated differences of mixture of the 
infmitcly manifold combinations ■ of albumen are not appre- 
ciable by the rude and imperfect means of human observation, 
and are, consequently, at present of no further interest to 
the task we have in hand. 

The question of the monophyletic or polyphyletic origin 
wiU constantly recur within each individual tribe, where 
the origin of a smaller or of a larger group is discussed. In 
the vegetable kingdom, for example, some botanists wiU be 
inclined to derive all flowering plants from a single form of 
fern, while others will prefer the idea that several different 
groups of Phanerogama have sprung from several different 
groups of ferns. In like manner, in the animal kingdom, 


some zoologists will be more in favour of the supposition 
that all placental animals are derived from a single pouched 
animal ; others will be more in favour of the opposite sup- 
position, that several different groups of placental animals 
have proceeded from several different pouched animals. In 
regard to the human race itself, some will prefer to derive 
it from a single form of ape, while others wiU be more 
inclined to the idea that several different races of men have 
arisen, independently of one another, out of several different 
species of ape. Without here expressing our opinion in 
favour of either the one or the other conception, we must, 
nevertheless, romark that in general the monophyletic 
hypothesis of descent deserves to he preferred to the 
polyp)hyletic hypothesis of descent. In accordance with the 
chorological proposition of a single " centre of creation" 
or of a single primteval home for most species (which has 
already been discussed), we may be permitted to assume 
that the original form of every larger or smaller natural 
group only originated once in the course of time, and only 
in one part of the earth. We may safely assume this 
simple original root, that is, the monophyletie origin, in the 
case of all the more highly develoi^ed groups of the animal 
and vegetable kingdoms. (Compare vol. i. p. 353). But it is 
very possible that the more complete Theory of Descent of 
the future wiU involve the polyphyletic origin of very 
many of the low and imperfect groups of the two oi'ganic 

For these reasons I consider it best, in the mean time, to 
adopt the monophyletie hypothesis of descent both for the 
animal and for the vegetable kingdom. Accordingly, the 
above-mentioned six tribes, or phyla, of the animal kingdom 


must be connected at their lowest root, and likewise the 
three or six main classes, or phyla, of the vegetable kingdom 
must be traced to a common and most ancient original form. 
How the connection of these tribes is to be conceived I shall 
explain in the succeeding chapters. But before proceeding to 
this, we must occupy ourselves with a very remarkable group 
of organisms, which cannot without artificial constraint be 
assigned either to the pedigree of the vegetable or to that of 
the animal kingdom. These interesting and important 
organisms are the prvmary creatures, or Protista. 

All organisms which we comprise under the name of 
Protista show in their external form, in their inner struc- 
ture, and in all their vital phenomena, such a remarkable 
mixture of animal and vegetable properties, that they cannot 
with perfect justice be assigned either to the animal or to 
the vegetable kingdom; and for more than twenty years an 
endless and fruitless dispute has been carried on as to 
whether they are to be assigned to this or that kingdom. 
Most of the Protista are so small that they can scarcely, if 
at all, be perceived with the naked eye. Hence the ma- 
jority of them have only become known during the last 
fifty years, since by the help of the improved and general 
use of the microscope these minute organisms have been 
more frequently observed and more accurately examined. 
However, no sooner were they better known than endless 
disputes arose about their real nature and their position in 
the natural system of organisms. Many of these doubtful 
primary creatures botanists defined as animals, and zoolo- 
gists as plants ; neither of the two would own them. Others, 
again, were declared by botanists to be plants, and by 
zoologists to be animals ; each claimed them. These contra- 


dictions are not altogether caused by our imperfect know- 
ledge of the Protista, but in reality by their true nature. 
Indeed, most Protista present such a confused mixture of 
several animal and vegetable characteristics, that each in- 
vestigator may arbitrarily assign them either to the animal 
or vegetable kingdom. Accordingly as he defines these 
two kingdoms, and as he looks upon this or that cha- 
racteristic as determining the animal or vegetable nature, 
he will assign the individual classes of Protista in one case 
to the animal and in another to .the vegetable kingdom. But 
this systematic difSeulty has become an inextricable knot 
by the fact that all more recent investigations on the lowest 
organisms have completely effaced, or at least destroyed, the 
sharp boundary between the animal and vegetable king- 
dom which had hitherto existed, and to such a degree that 
its restoration is possible only by means of a completely 
artificial definition of the two kingdoms. But this defini- 
tion could not be made so as to apply to many of the 

For this and other reasons it is, in the mean time, best 
to exclude the doubtful beings from the animal as well 
as from the vegetable kingdom, and to comprise them in a 
third organic kingdom standing midway between the two 
others. This intermediate kingdom I have established as 
the Kingdom^ of ilm Primary Creatures (Protista), when 
discussing general anatomy in the first volume of my 
General Morphology, p. 191-238. In my Monograph of 
the Monera,^^ I have recently treated of this kingdom, 
having somewhat changed its limits, and given it a more 
accurate definition. Of independent classes of the kingdom 
Protista, we may at present distinguish the following; — 


1. The still living Monera ; 2. The Amoeboidea, or Protoplasts ; 
3. The Whip-swimmers, or Flagellata; 4. The Flimmer-balls, 
or Catallacta ; 5. The Tram-weavers, or Labyrinthuleae ; 
6. The Flint-cells, or Diatomese ; 7. The Slime-moulds, 
or Myxomycetes ; 8. The Pi.ay-streamers, or Rhizopoda. 

The most important groups at present distinguishable in 
these eight classes of Protista are named in the systematic 
table on p. 51. Probably the number of these Protista 
will be considerably increased in future days by the pro- 
gressive investigations of the ontogeny of the simplest forms 
of life, which have only lately been carried on with any great 
zeal. With most of the classes named we have become 
intimately acquainted only during the last ten years. The 
exceedingly interesting Monera and Labyrinthulese, as also 
the Catallacta, were indeed discovered only a few years ago 
It is probable also that very numerous groups of Protista 
have died out in earlier periods, without having left any 
fossil remains, owing to the very soft nature of their bodies. 
We might add to the Protista from the still living lowest 
groups of organisms — the Fungi ; and in so doing should 
make a very large addition to its domain. Provisionally we 
shall leave them among plants, though many naturalists 
have separated them altogether from the vegetable kingdom. 

The pedigree of the kingdom Protista is still enveloped 
in the greatest obscurity. The peculiar combination of 
animal and vegetable properties, the indifferent and un- 
certain character of their relations 01 forms and vital 
phenomena, together with a number of several very.peculiar 
features which separate most of the subordinate classes 
sharply from the others, at present baffle every attempt 
distinctly to make out their blood relationships with one 


another, or with the lowest animals on the one hand, and 
with the lowest plants on the other hand. It is not improb- 
able that the classes specified, and many other unknown 
classes of Protista, represent quite independent organic 
tribes, or phyla, each of which has independently developed 
from one, perhaps from various, Monera which have arisen by 
spontaneous generation. If we do not agree to this poly- 
phyletic hypothesis of descent, and prefer the monophyletic 
hypothesis of the blood relationship of all organisms, we 
shall have to look upon the different classes of Protista as 
the lower small offshoots of the root, springing from the same 
simple Monera root, out of which arose the two mighty and 
many-branched pedigrees of the animal kingdom on the one 
hand, and of the vegetable kingdom on the other. (Com- 
pare pp. 74, 7^.) Before I enter into this difficult question 
more accurately, it wiU be appropriate to premise something 
further as to the contents of the classes of Protista given on 
the next page, and their general natural history. 

It will perhaps seem strange that I should here a<Tain 
begin with the remarkable Monera aS: the first class of 
the Protista kingdom, as I of course look upon them as 
the most ancient primary forms of all oi-ganisms without 
exception. Still, what are we otherwise to do with the still 
living Monera ? We know nothing of their palseontological 
origin, we know nothing of any of their relations to lower 
animals or plants, and we know nothing of their possible 
capability of developing into higher organisms. The simple 
and homogeneous little lump of slime or mucus which consti- 
tutes their entire body (Fig. 8) is the most ancient and 
original fonn of animal as well as of vegetable plastids. 
Hence it would evidently be just as arbitrary and unreason- 




0/ tliQ Larger and Smaller Groups of the Kivgdom Protista. 

Classes of 

the. ProliRta 


Sifstemattc Nome 
oj'ilia Classes. 

Orders of 

Families of Hie 


A name of a 


as an example- 



3. Whip-swim- ( 

ME Its 




6. Flint-cblls 


Flasellata A 



Diatomea { 

7. Slime-modlds Myxomycetes '. 

8. Eay-stheam- 
ers, oe b,hi- 



' I. Acyttaria 

, II. Heliozoa 

III. Eadiolaria ■ 

1. Gymnomonera 

2. Lepomonera 

1. GymnanKEbaj 

2. Lepamcebos 

3. Grogarina3 

1. Nudiflagellata 

2. Cilioflagellata 

1. Catallacta 

1. Lab^rintliiilese 

1. Striata 

2. Vittata 

3. Areolata 

1. PhysareaB 

2. Stemonitcse 

3. Trichiacess 

4. Lycogaleae 

1. Monothalamia 

2. Polythalamia 

1. Heliozoa 

1. Monocyttaria 

2. Folyoyttaria 












able to assign them to the animal as it would be to assign 
them to the vegetable kingdom. In any case we shall for 
the present be acting more cautiously and critically if we 
comprise the still living Monera — whose number and dis- 
tribution is probably very great — as a special and inde- 
pendent class, contrasting them with the other classes of the 
kingdom Protista, as well as with the animal kingdom. 
Morphologically considered, the Monera — on account of the 
perfect homogeneity of the albuminous substance of their 





Fio. 8. — ProtaTDOjba primitiva, a frpsn-wiacr Moir^roTi, mnch enlarpind. 
A. The entire Moneron with its forui-ohaagiug processes. B. It Ijsyms to 
divide itself into two halves. C. The division of the two halves is com- 
pleted, and each now repre.'ients an independent individual. 

bodies, on account of their utter want of heterogeneous 
particles — are more closely connected with anorgana than 
with organisms, and evidently form the transition between 
the inorganic and organic world of bodies, as is necessitated 
by the hypothesis of spontaneous generation. I have 
described and given illustrations of the forms and vital 
phenomena of the still living Monera (Protamceba, Proto- 
genes, Protoinyxa, etc.) in my Monograph of the Monera,^'' 
and have briefly mentioned the most, important facts in 
the eighth chapter (vol. i. pp. 183-187). Therefore, only by 
way of a specimen, I here repeat the drawing of the fresh- 



water Protamoeba (Fig. 8). The history of the life of an 
orange-red Protomyxa adrantiaca, which I observed at 
Lanzerote, one of the Canary Islands,: is given in Plate I. 
(see its explanation in the Appendix). Besides this, I here 
add a drawing of the form of Bathybius, that remarkable 
Moneron discovered by Huxley, vrhich lives in the greatest 
depths of the sea in the shape of naked lumps of pro- 
toplasm and reticular mucus (vol. i. p. 344). 

Fig. 9. — Bathybins Hsec- 
kelii, the " creature of primaeval 
slime," from the greatest depths 
of the sba. The figure, which ia 
gi'eatlj magnified, only shows 
that form of the Bathybius which 
consists of a naked network of 
protoplasm, without the disco- 
liths and cyatholiths which are 
found in other forms of the same 
Moneron, and which perhaps may 
be considered as the products of 
its secretion. 

The AmaebcB of the present day, and the organisms most 
closely connected v/ith them, Arcellidoe and GregarincB, 
which we here unite as a second class of Protista under 
the name of Amceboidea (Protoplasta), present no fewer 
genealogical diiSculties than the Monera, These primary 
creatures are at present usually placed in the animal 
kingdom without its in reality being understood why. 
For simple naked cells — that is, shell-less plastids with a 
kernel — occur as well among real plants as real animals. 
The generative cells, for example, in many Algfe (spores 
and eggs) exist for a longer or shorter time in water in the 


form of naked cells with a kernel, which cannot be distin- 
guished at all from the naked eggs of many animals (for 
example, those of the Siphonophorous Medusae). (Compare 
the figure of a naked egg of a bladder- wrack in Chapter 
xvii. p. 90). In reality every naked simple cell, whether 
ifc proceeds from an animal or vegetable body, cannot 
be distinguished from an independent Amoeba. For an 
Amoeba is nothing but a simple primary cell, a naked 
little lump of cell-matter, or plasma, containing a kernel. 
The contractility of this plasma, which the free Amoeba 
shows in stretching out and drawing in its changing pro- 
cesses, is a general vital property of the oi-ganic plasma 
of all animal as well as of all vegetable plastida When a 
freely moving AmcBba, which perpetually changes its form, 
passes into a state of rest, it draws itself together into the 
form of a globule, and surrounds itself with a secreted mem- 
brane. It can then be as little distinguished from an anima) 
egg as from a simple globular vegetable cell (Fig. 10 A). 

Frc. 10. — srihrcrocnccos, greatly magnified. A t'resh-water Amoeba 
without a contractile vacuole. A. The enclosed Amoeba in the state 
of a globular lump of plasma (c) enclosing a kernel and a kernel-speck (a). 
The simple cell is surrounded by a cyst, or cell-membrane (d). B, The 
free Amoeba, which has burst and left the cyst, or ceU-membrane. C. It 
begins to divide by its kernel parting into two kernels, and the cell- 
substance between the two contracting. I). The division is completed, and 
the oell-sabstance has entirely sejiarated into two bodies. (Da and Db). 


Naked cells, with kernels, like those represented in 
Fig. 10 B, which are continuously changing, stretching out 
and drawing in formless, finger-like processes, and which 
are on this account called amoeboid, are found frequently 
and widely dispersed in fresh water and in the sea ; nay, are 
even found creeping on land. They take their food in the 
same way as was previously described in the case of the 
Protamoeba (vol. i. p. 186). Their propagation by division 
can sometimes be observed (Fig. 10 C, D.) I have described 
the processes in an earlier chapter (voL i. p. 187). Many of 
these formless Amoebse have lately been recognized as the 
early stages of development of other Protista (especially 
the Myxomycetas), or as the freed cells of lower animals and 
plants. The colourless blood-cells of animals, for example, 
those of human blood, cannot be distinguished from Amoebso. 
They, like the latter, can receive solid corpuscles into their 
interior, as I was the first to show by feeding them with 
finely divided colom-ing matters (Gen. Morph. i. 271). How- 
ever, other Amoebse (like the one given in Fig. 10) seem to 
be independent " good species," since they propagate them- 
selves unchanged throughout many generations. Besides 
the real, or naked, Amoebse (Gymnamoeba!), we also find 
widely diffused in fresh water case-hearing Amoebge (Lep- 
amoebse), whose naked plasma body is partially protected 
by a more or less solid shell (Arcella), sometimes even by 
a case (Difflugia) composed of small stones. Lastly, we 
frequently find in the body of many lower animals parasitic 
Amoebae (Gregarinae), which, adapting themselves to a para- 
sitic hfe, have surrounded their plasma-body with a, delicate 
closed membrane. 

The simple naked Amoebse are, next to the Monera, the 


most important of all organisms to the whole science of 
biology, and especially to general genealogy. For it is 
evident that the Amoebae originally arose out of simple 
Monera (Protamoebse), by the important process of segre- 
gation taking place in their homogeneous viscid body — the 
differentiation of an inner kernel from the surrounding 
plasma. By this means the great progress from a simple 
cytod (without kernel) into a real cell (with kernel) was 
accomplished (compare Fig. 8 A and Fig. 10 B). As some of 
these cells at an early stage encased themselves by secreting 
a hardened membrane, tliey formed the first vegetable cells, 
while others, remaining naked, developed into the first 
aggregates of animal cells. The presence or absence of an 
encircling hard membrane forms the most important, 
although by no means the entire, difference of form between 
animal and vegetable cells. As vegetable cells even at an 
early stage enclose themselves within their hard, thick, and 
solid cellular shell, like that of the Amosbge in a state of rest 
(Fig. 10 A), they remain more independent and less accessible 
to the influences of the outer world than are the soft animal 
cells, which are in most cases naked, or merely covered by a 
thin pliable membrane. But in consequence of this the 
vegetable cells cannot combine, as do the animal cells, for 
the construction of higher and composite fibrous tracts, for 
example, the nervous and muscular tissues. It is probable 
that, in the case of the most ancient single-celled organisms, 
there must have developed at an early stage the very im- 
portant difference in the animal and vegetable mode of 
receiving food. The most ancient single-celled animals, being 
naked ccUs, could admit solid particles into the interior of 
their soft bodies, as do the Amcebas (Fig. 10 B) and the 



colourless blood-cells ; whereas the most ancient single- 
celled plants encased by their membranes were no longer 
able to do this, and could admit through it only fluid 
nutrition (by means of diffusion). 

The Whip-swimmers (Flagellata), which we consider as a 
third class of the kingdom Protista, are of no less doubtful 
nature than the Amoebae. They often show as close and 
important relations to the vegetable as to the animal 
kingdom. Some Flagellata at an early stage, when freely 
moving about, cannot be distinguished from real plants, 
especially from the spores of many Algsa; whereas others 
are directly aUied to real animals, namely, to tlie fringed 

Fig. 11. — A single Whip-swimmer (Engiana, striata), greatly 
magnified. Above a thread-like lashing whip is visible; in 
the centre the round cellular kernel, with its kernel speck. 

Infusoria (Ciliata). The Flagellata are simple 
cells which live in fresh or salt water, either 
singly or united in colonies. The characteristic 
part of their body is a very movable simple 
or compound whip-like appendage (whip, or 
flagellum) by means of which they actively 
swim about in the water. This class is divided 
into two orders. Among the fringed whip- 
.svi'lmmers (Cilioflagellata) there exists, in addition to the 
long whip, a short fringe of vibrating hairs, which is wanting 
in the unfringed whip-swimmers (Nudoflagellata). To the 
former belong the flint-sheUed yellow Peridinia, which are 
largely active in causing the phosphorescence of the sea ; to 
the latter belong the green Euglense, immense masses of 
which frequently make our ponds in spring quite green. 



A very remarkable new form of Protista, which I have 
named Flimmer-ball (Magosphsera), I discovered only three 
years ago (in September, 1869), on the Norwegian coast 
(Fio-. 12), and have more accurately described in my 

Fig. 12. — The ISTorwegian Flim- 
mer-ball (Magosphaera planula) 
swimming by means of its vibra- 
tile fringes, as seen from the 

Biological Studies ^® (p 
137, Plate V.). Off the 
island of Gis-oe, near Ber- 
gen, I found swimming 
about, on the surface of 
the sea, extremely neat 
little balls composed ot a number (between thkty and forty) 
of fringed pear-shaped cells, the pointed ends of which were 
united in the centre hke radii After a time the ball dis- 
solved. The individual cells swarmed about independently 
in the water like fringed Infusoria, or Ciliata. These after- 
wards sank to the bottom, drew their fringes into thcli- 
bodies, and gradually changed into the form of creeping 
Amoebfe (like Fig. 10 B). These last afterwards encased 
themselves (as in Fig. 10 A), and then divided by repeated 
halvings into a large number of cells (exactly as in the case 
of the cleavage of the egg, Fig. 6, vol. L p. 299). The cells 
became covered with vibratile hairs, broke through the case 
enclosing them, and now again swam about in the shape of 
a fringed ball (Fig. 12). This wonderful organism, which 
sometimes appears like a simple Amoeba, sometimes as a 



single fringed cell, sometimes as a many-celled fringed ball, 
can evidently be classed with none of the other Protista, 
and must be considered as the representative of a new 
independent group. As this group stands midway between 
several Protista, and links them together, it may bear the 
name of Mediator, or Gatallacta. 

The Protista of the fifth class, the Tram-weavers, or 
LahyrinthuleoB, are of a no less puzzling nature ; they were 
lately discovered by Cienkowski on piles in sea water (Fig. 
13). They are spindle-shaped cells, mostly of a yellow- 

FiG. 13. — Labyrinthula macro- 
cystia (much enlarged). Below 
is a large group of accamnlated 
cells, one of which, on the left, 
is separating itself; above are 
two single cells which are gliding 
along the threads of the reti- 
form labyrinth which form their 
*' tramways." 

ochre colour, which are 
sometimes united into a 
dense mass, sometimes 
move about in a very 
peculiar way. They form, 
in a manner not yet explained, a retiform frame of en- 
tangled threads (compared to a labyrinth), and on the 
dense filamentous "tramways" of this frame they glide 
about. From the shape of the cells of the Labyrlnthuleas we 
might consider them as the simplest plants, from their 
motion as the simplest animals, but in reality they are 
neither animals nor plants. 



Fig. 14. — NavJcula hippocaiiipns (greatly magtiified). 
In the middle of the cell the cell-kernel (nuclens) is 
visible, together with its kernel speck (nucleolus). 

The Flint-cells (Diatomese), a sixth class of 
Protista, are perhaps the most closely related 
to the Labyrinthuleas. These primary crea- 
tures — which at present are generally con- 
sidered as plants, although some celebrated 
naturalists still look upon them as animals — 
inhabit the sea and fresh waters in immense 
masses, and offer an endless variety of the 
most elegant forms. They are mostly small microscopic 
cells, which either live singly (Fig. 14), or united in great 
numbers, and occur either attached to objects, or glide and 
creep about in a peculiar manner. Their soft cell substance, 
which is of a characteristic brownish yellow colour, is 
always enclosed by a solid and hard flinty shell, possessing 
the neatest and most varied forms. This flinty covering is 
open to the exterior only by one or two slits, through 
which the enclosed soft plasma-body communicates with 
the outer world. The flinty cases are found petrified in 
masses, and many rocks — ^for example, the Tripoli slate 
polish, the Swedish mountain meal, etc., — are in a great 
measure composed of them. 

A seventh class of Protista is formed by the remarkable 
Slinie-moulds (Myxomycetes). They were formerly uni- 
versally considered as plants, as real Fungi, until ten years 
ago the botanist De Bary, by discovering their ontogeny, 
proved them to be quite distinct from Fungi, and rather 
to be akin to the lower animals. The mature body is a 


Fig. 15. — A stalked fruit-body (spore.bladder, filled 
with spores) of one of the Myiomyoetes (Physarnm 
albipes) not much enlarged. 

roundish bladder, often several inches in 
size, filled with fine spore-dust and soft 
flakes (Fig. 15), as in the case of the ■well- 
known puff-balls (Gastromycetes). How 
ever, the characteristic cellular threads, or 
hyphae, of a real fungus do not arise from 
the germinal corpuscles, or spores, of the Myxomycetes, but 
merely naked masses of plasma, or cells, which at first swim 
about in the form of Flagellata (Fig. 11), afterwards creep 
about like the Amoebae (Fig. 10 B), and finally combine 
with others of the same kind to form large masses of " slime," 
or " Plasmodia." Out of these, again, there arises, by-and-by, 
the bladder-shaped fruit-body. Many of my readers prob- 
ably know one of these plasmodia, the iEthalium septicum, 
which in summer forms a beautiful yellow mass of soft 
mucus, often several feet in breadth, known by the name of 
" tan flowers," and penetrates tan-heaps and tan-beds. At 
an early stage these slimy, freely-creeping Mj^xomycetes, 
which live for the most part in damp forests, upon decaying 
vegetable substances, bark of trees, etc., are with equal justice 
or injustice declared by zoologists to be animals, while in the 
mature, bladder-shaped condition of fructification they are 
by botanists defined as plants. 

The nature of the Ray-streamers (Rhizopoda), the eighth 
class of the kingdom Protista, is equally obscure. These 
remarkable organisms have peopled the sea from the most 
ancient times of the organic history of the earth, in an 


immense variety of forms, sometimes creeping at the bottom 
of the sea, sometimes swimming on the surface. Only very 
few live in fresh water (Gromia, Actinosphaarium). Most of 
them possess solid calcareous or flinty shells of an extremely 
beautiful construction, which can be perfectly preserved in a 
fossil state. They have frequently accumulated in such 
huo-e numbers as to form mountain masses, although the 
single individuals are very small, and often scarcely visible, or 
completely invisible, to the naked eye. A very few attain 
the diameter of a few lines, or even as much as a couple 
of inches. The name which the class bears is given 
because thousands of exceedingly fine threads of protoplasm 
radiate from the entire surface of their naked slimy body ; 
these rays are quasi-fect, or pseudopodia, which branch off 
like roots (whence the term Ehizopoda, signifying root- 
footed), unite like nets, and are observed continually to 
change fonn, as in the case of the simpler plasmic feet of 
the Amoeboidea, or Protoplasts. These ever-changing little 
pseudo-feet serve both for locomotion and for taking food. 

The class of the Rhizopoda is divided into three different 
legions, viz. the chamber-shells, or Aeyttaria, the sun-animal- 
cules, or Heliozoa, and the basket-shells, or Eadiolaria. The 
Ghamher-sliells (Aeyttaria) constitute the first and lowest of 
these three legions ; for the whole of their soft body consists 
merely of simple mucous or slimy cell-matter, or proto- 
plasm, which has not differentiated into cells. However, 
in spite of this most primitive nature of body, most of the 
Aeyttaria secrete a solid shell composed of calcareous earth, 
which presents a gi-eat variety of exquisite forms. In the 
more ancient and more simple Aeyttaria this shell is a 
simple chamber, bell-shaped, tubular, or like the shell of 


a snail, from the mouth of which a bundle of plasmic 
threads issues. In contrast to these single-chamhered forms 
(Monothalamia), the raany-diambered forms (Polythal- 
amia) — to which the great majority of the Acyttaria 
belong — possess a house, which is composed in an artistic 
manner of numerous chambers. These chambers sometimes 
lie in a row one behind the other, sometimes in concentric 
circles or spirals, in the form of a ring round a central point, 
and then frequently one above another in many tiers, like the 
boxes of an amphitheatre. This formation, for example, is 
found in the nummulites, whose calcareous shells, of the size 
of a lentil, have accumulated to the number of millions, and 
form whole mountains on the shores of the Mediterranean. 
The stones of which some of the Egyptian pyramids are 
built consist of such nummulitic limestone. In most cases 
the chambers of the shells of the Polythalamia are wound 
round one another in a spiral Hne. The chambers are con- 
nected with one another by passages and doors, like rooms 
of a large palace, and are generally open towards the outside 
by numerous little windows, out of which the plasmic body 
can stream or strain forth its little pseudo-feet, or rays of 
sHme, which are always changing form. But in spite of the 
exceedingly complicated and elegant structure of this cal- 
careous labyriath, in spite of the endless variety in the 
structure and the decoration of its numerous chambers, and 
in spite of the regularity and elegance of their execution, 
the whole of this artistic palace is found to be the secreted 
product of a perfectly formless, slimy mass, devoid of any 
component parts ! Verily, if the whole of the recent 
anatomy of animal and vegetable textures did not support 
our theory of plastids, if all its impori^ant results did not 


unanimously corroborate the fact that the whole miracle of 
vital phenomena and vital forms is traceable to the 
active agency of the formless albuminous combinations of 
protoplasm, the Polythalamia alone would secure the 
triumph of that theory. For we may here at any moment, 
by means of the microscope, point out the wonderful fact, 
first established by Dujardin and Max Schulze, that the 
formless mucus of the soft plasma-body, this true*' matter of 
life," is able to secrete the neatest, most, regular, and most 
complicated structures. This secretive skill is simply a 
result of inherited adaptation, and by it we learn to under- 
stand how this same " primaeval slime " — this same proto- 
plasm — can produce in the bodies of animals and plants 
the most different and most complicated cellular forms. 

It is, moreover, a matter of special interest that the most 
ancient organism, the remains of which are found in a petri- 
fied condition, belongs to the Polythalamia. This organism is 
the " Canadian Life's-dawn " (Eozoon canadense), which has 
already been mentioned, and which was found a few years 
ago ia the Ottawa formation (in the deepest strata of the 
Laurentian system), on the Ottawa river in Canada. If we 
expected to find organic remains at all in these most ancient 
deposits of the primordial period, we should certainly look 
for such of the most simple Protista as are covered with a 
solid shell, and in the organization of which the difference 
between animal and plant is as yet not indicated. 

We know of but few species of the Sun-animalcules 
(Heliozoa), the second class of the Rhizopoda. One species is 
very frequently found in our fresh waters. It was observed 
even in the last century by a clergyman in Dantzig, Eichhorn 
by name, and it has been called after hiru, Actinosphperium 


Eichhornii. To the naked eye it appears as a gelatinous 
grey globule of mucus, about the size of a pia's head 
Looking at it through the microscope, we see hundreds or 
thousands of fine mucous threads radiating from the central 
plasma body, and perceive that the inner layer of its ceU- 
substance is different from the outer layer, which forms a 
bladder-like membrane. In consequence of its structure, this, 
the httle sun-animalcule, although wanting a shell, really 
rises above the structureless Acyttaria, and forms the 
transition from these to the Eadiolaria. The genus Cysto- 
phrys is of a nature akin to it. 

The Basket-shells (Radiolaria) form the third and last 
class of the Ehizopoda. Their lower forms are closely allied 
to the Heliozoa and Acyttaria, whereas their higher forms 
rise far above them. They are . essentially distinguished 
from both by the fact that the central part of their body is 
composed of many cells, and surrounded by a solid mem- 
brane. This closed "central capsule," generally of a glo- 
bular shape, is covered by a mucous layer of plasma, out of 
which there radiate on all sides thousands of exceedingly fine 
threads, the branching and confluent so-eaUed pseudopodia. 
Between these are scattered numerous yellow cells of un- 
known function, containing grains of starch. Most Radio- 
laria are characterized by a highly developed skeleton, 
which consists of flint, and displays a wonderful richness of 
the neatest and most curious forms. Sometimes this flinty 
skeleton forms a simple trellice-work ball (Fig. 16 s), some- 
times a mai-vellous system of several concentric treUiced balls, 
encased iu one another, and coimected by radial staves. In 
most cases delicate spikes, which are frequently branched 
like a tree, radiate from the surface of the baUs. In other 




cases the whole skeleton consists of only one flinty star, and 
is then generally composed of twenty staves, distributed 
according to definite mathematical laws, and united in a 

1''|G. Ifi. — Oyrtidosphacra echinoifles, 400 times enlarged, e. Globular 
central eapsnle. s. Basket-work of the perforated flinty shell. a. Radial 
spikes, which radiate from the latter. j>. The pseudo-feet radiating from 
the mucous covering surrounding the central capsule. I. Yellow globular 
cells, scattered between the latter, containing grains of starch. 

common central point. The skeletons of other Radiolaria 
again form symmetrical many-chambered structures, as in 
tlie ease of the Polythalamia. Perhaps no other group of 


organisms develop in the formation of their skeletons such 
an amount of various fundamental forms, such geometrical 
regularity, and such elegant architecture. Most of the forms 
as yet discovered, I have given in the atlas accompanying 
my Monograph of the Radiolaria.^ Here I shall only 
give as an example the picture of one of the simplest 
forms, the Cyrtidosphcera ecJdnoides of Nice. The skeleton 
in this case consists only of a simple treUiced ball (s), with 
short radial spikes (a), which loosely surround the central 
capsule (c). Out of the mucous covering, enclosing the 
latter, radiate a great number of delicate little pseudopodia 
(p), which are partly drawn back underneath the shell, and 
fused into a lumpy mass of mucus. Between these are 
scattered a number of yellow cells (I). 

Most Acyttaria live only at the bottom of the sea, on stones 
and seaweeds, or creep about in sand and mud by means 
of their pseudopodia, but most Radiolaria swim on the 
surface of the sea by means of long pseudopodia extending in 
all directions. They Uve together there in immense numbers, 
but are mostly so small that they have been almost com- 
pletely overlooked, and have only become accurately known 
during the last fourteen years. Certain Eadiolaria living 
in communities (Polycyttaria) form gelatinous lumps of some 
lines in diameter. On the other hand, most of those living 
isolated (Monocyttaria) are invisible to the naked eye ; but 
still their petrified sliells are found accumulated in such 
masses that in many places they form entire mountains ; for 
example, the Nicobar Islands in the Indian Aixhipelago, and 
the Island of Barbadoes in the Antilles. 

As most readers are probably but little acquainted 
with the eight classes of the Protista just mentioned, I shall 


now add some further general observations on their 
natural history. The great majority of all Protista 
live in the sea, some swimming freely on the surface, 
some creeping at the bottom, and others attached to 
stones, shells, plants, etc Many species of Protista also live 
in fresh water, but only a very small number on dry land 
(for example, Myxomycetes and some Protoplasta). Most 
of them can be seen only through the microscope, except 
when millions of individuals are found accumulated. Only 
a few of them attain a diameter of some lines, or as much 
as an inch. Wliat they lack in size of body they make up 
for by producing astonishing numbers of individuals, and 
they very considerably influence in this way the economy of 
nature. The imperishable remains of dead Protista, for 
instance, the flinty shells of the Diatomese and Radiolaria 
and the calcareous shells of the Acyttaria, often form large 
rock masses. 

In regard to their vital phenomena, especially those of 
nutrition and propagation, some Protista are more allied to 
plants, others more to animals. Both in their mode of 
taking food and in the chemical changes of their living sub- 
stance, they sometimes more resemble the lower animals, at 
others the lower plants. Free locomotion is possessed by 
many Protista, while others are without it ; but this does 
not constitute a characteristic distinction, as we know of 
undoubted animals which entirely lack free locomotion, and 
of genuine plants which possess it. All Protista have 
a soul — that is to say, are "animate " — as well as all animals 
and all plants. The soul's activity in the Protista manifests 
tself in their irritability, that is, in the movements and, 
iother changes which take place in consequence of median. 


ical, electrical, and chemical irritation of their contractile 
protoplasm. Consciousness and the capability of wiU and 
thought are probably wanting in all Protista. However, the 
same qualities are in the same degree also wanting in many 
of the lower animals, whereas many of the higher animals 
in these respects are scarcely inferior to the lower races of 
hiunan beings. In the Protista, as in all other organisms, the 
activities of the soul are traceable to molecular motions in 
the protoplasm. 

The most important physiological characteristic of the 
kingdom Protista hes in the exclusively non-sexual pro- 
pagatio7i of all the organisms belonging to it. The higher 
animals and plants multiply almost exclusively in a sexual 
manner. The lower animals and plants multiply also, in 
many cases, in a non-sexual manner, by division, the form- 
ation of buds, the formation of germs, etc. But sexual 
propagation almost always exists by the side of it, and often 
regularly alternates with it in succeeding generations (Meta- 
genesis, vol. i. p. 20G). AU Protista, on the other hand, pro- 
pagate themselves exclusively in a non-sexual manner, and 
in fact, the distinction of the two sexes among them has 
not been effected — there are neither male nor female Protista. 

The Protista in regard to their vital phenomena stand 
midwa.y between animals and plants, that is to say, between 
their lowest forms ; and the same must be said m regard to 
the chemical composition of their bodies. One of the most 
important distinctions between the chemical composition of 
animal and vegetable bodies consists in the characteristic 
formation of the skeleton. The skeleton, or the solid scaffold- 
ing of the body in most genuine plants, consists of a sub- 
stance called cellulose, devoid of nitrogen, hut secreted by the 


nitrogenous cell-substance, or protoplasm. In most genuine 
animals, on the other hand, the skeleton generally consists 
either of nitrogenous combinations (chitin, etc.) or of cal- 
careous earth. In this respect some Protista are more like 
plants, others more like animals. In many of them the 
skeleton is principally or entirely formed of calcareous earth, 
which is met with both in animal and vegetable bodies. 
But the active vital substance in all cases is the mucous 

In regard to the form of the Protista, it is to be remarked 
that the individuality of their body almost always remains 
at an extremely low stage of development. Very many Pro- 
tista remain for life simple plastids or individuals of the first 
order. Others, indeed, form colonies or republics of plastids 
by the union of several individuals. But even these higher 
individuals of the second order, formed by the combination 
of simple plastids, for the most part remain at a very low 
stage of development. The members of such communities 
among the Protista remain very similar one to another, and 
never, or only in a slight degree, commence a division of 
labour, and are consequently as little able to render their 
community fit for higher functions as are, for example, the 
savages of Australia. The community of the plastids re- 
mains in most cases very loose, and each single plastid 
retains in a great measure its own individual independence. 

A second structural characteristic, which next to their low 
stage of individuality especially distinguishes the Protista, 
is the low stage of development of their stereometrical 
fundamental forms. As I have shown in my theory of 
fundamental forms (in the fourth book of the General 
Morphology), a definite geometrical fundamental form can 


be pointed out in most organisms, both in the general form 
of the body and in the form of the individual parts. This 
ideal fundamental form, or type, which is determined by the 
number, position, combination, and differentiation of the 
component parts, stands in just the same relation to the real' 
organic form as the ideal geometrical fundamental form of 
crystals does to their imperfect real form. In most bodies 
and parts of the bodies of animals and plants this fundamental 
form is a pyramid. It is a regular pyramid in the so-called 
" regular radiate " forms, and an irregular pyramid in the 
more highly differentiated, so-caUcd " bilaterally symmetri- 
cal " forms. (Compare the plates in the first volume of my 
General Moqihology, pp. 55G-558.) Among the Protista this 
pyramidal type, vi^hich prevails in the animal and vegetable 
kingdom, is on the whole rare, and instead of it we have 
either quite irregular (amorphous) or more simple, regular 
geometrical types; especially frequent are the sphere, the 
cylinder, the ellipsoid, the spheroid, the double cone, the cone, 
the regular polygon (tetrahedron, hexhahedron, octahedron, 
dodecahedron, icosahedron), etc. All the fundamental forms 
of the pro-morphological system, which are of a low rank in 
that system, prevail ia the Protista. However, in many 
Protista there occur also the higher, regular, and bilateral 
types, fundamental forms which predominate in the animal 
and vegetable kingdoms. In this respect some of the Protista 
are frequently more closely allied to animals (as the 
Acyttaria), others more so to plants (as the Radiolaria). 

With regard to the palceontological development of the 
kingdom Protista, we may form various, but necessarily very 
unsafe, genealogical hypotheses. Perhaps the individual 
classes of the kingdom are independent tribes, or phyla. 


which have developed independently of one another and 
independently of the animal and the vegetable kingdoms. 
Even if we adopt the monophyletic hypothesis of descent^ and 
maintain a common origin from a single form of Moneron for 
all organisms, without exception, which ever have lived and 
still live upon the earth, even in this case the connection 
of the neutral Protista on the one hand with the vegetable 
kingdom, and on the other hand with the animal 
kingdom, must be considered as very vagTie. We must 
regard them (compare p. 74) as lower offshoots which have 
developed directly out of the root of the great double- 
branched organic pedigree, or perhaps out of the lowest tribe 
of Protista, which may be supposed to have shot up midway 
between the two diverging high and vigorous trunks of the 
animal and vegetable kingdoms. The individual classes of 
the Protista, whether they are more closely connected at 
their roots in groups, or only form a loose bunch of root off- 
sets, must in this case be regarded as having nothing to do 
either with the diverging groups of organisms belonging to 
the animal kingdom on the right, or to the vegetable kingdom 
on the left. They must be supposed to have retained the 
original simple character of the common primaeval living 
thing more than have genuine animals and genuine plants. 

But if we ado]3t the polyphyletic hypothesis of descent, 
we have to imagine a number of organic tribes, or phyla, 
which all shoot up by spontaneous generation out of the 
same ground, by the side of and independent of one 
another. (Compare p. 75.) In that case numbers of dif- 
ferent Monera must have arisen by spontaneous generation 
whose differences would depend only upon slight, to us 
imperceptible, differences in their chemical composition, and 


consequently upon differences in their capability of develop- 
ment. A small number of Monera would then have given 
origin to the animal kingdom, and, again, a small number 
would have produced the vegetable kingdom. Between these 
two groups, however, there would have developed, indepen- 
dently of them, a largo number of independent tribes, which 
have remained at a lower stage of organization, and which 
have neither developed into genuine plants nor into genuine 

A safe means of deciding between the monophyletic and 
olyphyletic hypotheses is as yet quite impossible, consider- 
ing the imperfect state of our phylogenetic knowledge. The 
different groups of Protista, and those lowest forms of the 
animal kingdom and of the vegetable kingdom which are 
scarcely distinguishable from the Protista, show such a close 
connection with one another and such a confused mixture 
of characteristics, that at present any systematic division 
and arrangement of the groups of forms seem more or 
less artificial and forced. Hence the attempt here offered 
must be regarded as entirely provisional. But the more 
deeply we penetrate into the genealogical secrets of this 
obscure domain of inquirj'-, the more probable appears the 
idea that the vegetable kingdom and the animal kingdom 
are each of independent origin, and that midway between 
these two great pedigrees a number of other independent 
small o-roups of organisms have arisen by repeated acts of 
spontaneous generation, which on account of their indiSferent 
neutral character, and in consequence of their mixture of 
animal and vegetable properties, may laj"- claim to the 
designation of independent Protista. 

Thus, if we assume one entirely independent trunk for 




Utgctablc Iftingiom 

Flowering Plants 



9ttimal ISingtiom 

Vertebrate Animals 

Articulated Animals 




RIoUascoTis Animala 








^rimtrbal Plants Pvimaijal ffiHatutts primtciial animala 
Protophyta Protista Protozoa 

Vegetable Monera Neutral Jlonera Animal Monera 

attljigani: lIHontta 
(Pieces of Protoplasm which have originated by Spontaucons Generation) 












Mncons Fnngi 


PtimDcbal plants 




t t 







t t 

N.B. — The Lines marked with a f indicate extinct tribes of Protista, 
which hare arisen independently by repeated acts of Spontaneous Generation. 


the vegetable kingdom, and a second for the animal king- 
dom, we may set up a number of independent stems of 
Protista, each of which has developed, quite independently 
of other stems and trunks, from a special archigonic form of 
Monera. In order to make this relation more clear, we may 
imagine the whole world of organisms as an immense 
meadow which is partially withered, and upon which two 
many-branched and mighty trees are standing, likewise 
partially withered. The two great trees represent the 
animal and vegetable kingdoms, their fresh and still green 
branches the living animals and plants ; the dead branches 
with withered leaves j-epresent the extinct groups. The 
withered grass of the meadow corresponds to the numerous 
extinct tribes, and the few stalks, still green, to the still 
living phyla of the kingdom Protista. But the common 
soil of the meadow, from which all have sprung up, is 
primc3val by pnjlopla-aia. 


The Natural System of the Vegetable Kingdom. — Division of the Vepre- 
table Kingdom into S':; Branches and Eighteen Classes. — The 
Flowerlesg Plants (Cryptogamia). — Sub-kingdom of the Thallus 
Plants. — The Tangles, or Algae (Primary Algao, Green AlgiB, Brown 
■ Algae, Ked Alras.) —The Thread-plants, or Inophytes (Lichens and 
Fnngi.) — Sub-kingdom of the Prothallus Plants. — The Mosses, or 
Muscinae (Water.mossos, Liverworts, L«'af.mosscs, Bog-mosses). — The 
Perns, or Filicina) (Leaf-ferns, Bamboo-ferns, Water-ferns, Seale- 
ferns). — Sub-kingdom of Flowering Plants (Phanerogamia). — The 
C-rymnosperms, or Plants with Naked Seeds (Palm-ferns ^= CycadeBe ; 
Pines = Conif eras.) — The Angiosperms, or Plants with Enclosed Seeds. 
— "\Ior10cotyla3. — Dicotylas. — Cnp-blossoms (Apetalfe). — Star-blossoms 
(Diapctala;). — Ecll-blossoms (Gamopetalaj). 

EvEEY attempt that we make to gain a knowledge of the 
pedigree of any small or large group of organisms related 
by blood must, in the first instance, start with the evi- 
dence afforded by the existing "natural system" of this 
group. For although the natural system of animals and 
plants will never become finally settled, but will always 
represent a merely approximate knowledge of true blood 
relationship, stiU it will always possess great import- 
ance as a hypothetical pedigi'ee. It is true, by a " natui-al 
sj'.stem " most zoologLsts and botanists only endeavour to 
express in a concise way iihe subjective conceptions which 


each has formed of the objective " foi^i-relationships " of 
organisms. These form-relationships, however, as the reader 
has seen, are in reality the necessary result of true blood 
relationship. Consequently, every morphologist in promot- 
ing our knowledge of the natural system, at the same time 
promotes our knowledge of the pedigree, whether he wishes 
it or not. The more the natural system deserves its name, 
and the more firmly it is established upon the concordance 
of results obtained from the study of comparative anatomy, 
ontogeny, and palaeontology, the more surely may we con- 
sider it as the approximate expression of the true pedigree 
of the organic world. 

In entering upon the task contemplated in this chaptei*, 
the genealogy of the vegetable kingdom, we shall have, 
according to this principle, first to glance at the natural 
system of the vegetable kingdom as it is at present (with 
more or less important modifications) adopted by most 
botanists. According to the system generally in vogue, the 
whole series of vegetable forms is divided into two main 
groups. These main divisions, or sub-kingdoms, are the same 
as were distinguished more than a century ago by Charles 
LinniBus, the founder of systematic natural history, and 
which he called Cryptogamia, or secretly-blossoming plants, 
and Phanerogamia, or openly-flowering plants. The latter, 
LinnseuB, in his artificial system of plants, divided, accordino- 
to the different number, formation, and combination of Ca 
anthers, and also according to the distribution of the sexual 
organs, into twenty-three different classes, and then added 
the Cryptogamia to these as the twenty-fourth and last 

The Cryptogamia, the secretly-blossomiiig or llowerless 


plants, which were formerly but little ohserved, have in con- 
sequence of the careful investigations of recent times been 
proved to present such a great variety of forms, and such a 
marked difference in their coarser and finer structure, that 
we must distinguish no less than fourteen different classes 
of them ; whereas the number of classes of flowering plants, 
or Phanerogamia, may be limited to four. However, these 
eighteen classes of the vegetable kingdom can again be 
naturally grouped in such a manner that we are able to dis- 
tinguish in all six main divisions or branches of the vege- ■ 
table kingdom. Two of these six branches belong to the 
flowering, and four to the flowerless plants. The table on 
page 82 shows how the eighteen classes are distributed 
among the six branches, and how these again fall under the 
suh-hingdoms of the vegetable kingdom. 

The one sub-kingdom of the Cryptogamia may now be 
naturally divided into two divisions, or sub-kingdoms, differ- 
ing very essentially in their internal structure and in their 
external form, namely, the ThaUus plants and the ProthaUus 
plants. The group of Thallus plants comprises the two 
large branches of Tangles, or AJgse, which live in water, and 
the Thread-plants, or Inophytes (Lichens and Fungi), which 
gTOW on land, upon stone,s, bark of trees, upon decaying 
bodies, etc. The group of ProthaUus plants, on the other 
hand, comprises the two branches of Mosses and Ferns, 
containing a great variety of forms. 

All Thallus plants, or Thallophytes, can be directly recog- 
nized from the fact that the two morphological fundamental 
organs of aU other plants, stem and leaves, cannot be dis- 
tinguished in thoir structure. The complete body of aU 
Algse and of all Thread-plants is a mass composed of simple 



cells, wliicli is called a lohe, or tJiallus. This thallus is as 
yet Bot differentiated into axial-organs (stem and root) and 
leaf-organs. On this account, as well as through many 
other peculiarities, the Thallophytes contrast strongly with 
all remaining plants — those comjirised under the two sub- 
kingdoms of Prothallus plants and ^Flowering plants — and 
for this reason the two latter sub-kingdoms are frequently 
classed together under the name of Stemmed 2ila,7ils, or 
Cori7wphytes. The following table will explain the relation 
of these three sub-kingdoms to one another according to the 
two different views : — 

I. Flowovless Plants. 
( Cryptogamia) 

II. Flowering Plants 

A. Thallus Plants 

I B, Prothallus Plants 

f C. Flowering Plants 
j (Phanerogamia) j 

I. Thallus Plants 

II. Stemmed Plants 

The stemmed plants, or Cormophytes, in the organization 
of which the difference of axial-organs (stem and root) and 
leaf-organs is already developed, form at present, and have, 
indeed, for a very long period formed, the principal portion 
of the vegetable woild. However, this was not always the 
case. In fact, stemmed plants, not only of the flowering 
group, but even of the prothallus group, did not exist at all 
during that immeasurably long space of time which forms 
tlie beginning of the first gi-eat division of the organic 
history of the earth, under the name of the archilithic, or 
primordial period. The reader will recollect that durino- this 
period the Laurcntian, Cambrian, and Silurian systems of 
strata were deposited, the thickness of which, taken as a whole. 


amounts to about 70,000 feet. Now, as the thickness of all 
the more recent superincumbent strata, from the Devonian 
to the deposits of the present time, taken together, amounts 
to only about 60,000 feet, we were enabled from this fact 
alone to draw the conclusion — which is probable also for 
other reasons — that tlie archilithic, or primordial, period was 
of longer duration than the whole succeeding period down 
to the present time. During the whole of this immeasur- 
able space of time, which probably comprises many millions 
of centuries, vegetable life on our earth seems to have been 
represented exclusively by the sub-kingdom of Thallus 
plants, and, moreover, only by the class of marine Thallus 
plants, that is to say, the Algse. At least all the petrified 
remains which are positively known to be of the primordial 
period belong exclusively to this class. As all the animal 
remains of this immense period also belong exclusively to 
animals that lived in water, we come to the conclusion that 
at that time organisms adapted to a life on land did not 
exist at all. 

For these reasons the first and most imperfect of the great 
provinces or branches of the vegetable kingdom, the division 
of the Algse, or Tangles, must be of special interest to us. 
But, in addition, there is the interest which this group 
offers when viewed by itself. In spite of the exceedingly 
simple composition of their constituent cells, which are but 
little differentiated, the Algse show an extraordinary variety 
of different forms. To them belong the simplest and most 
imperfect of all forms, as well as very highly developed and 
peculiar forms. The different groups of Algte are dis- 
tinguished as much by size of body as by the peifcetion and 
variety of their outer form. At the lowest stage we find 




Of the Six Branches and Eighteen Glasses of the Vegetable 


Prhiiarii Groyps 
or Stth-Kiiifjdoins 

or llie 
Vef/etablc Aiiigdom. 

Brandies or Ckides 

of tlie 
VegeUihie. Kinr/dojii. 


of the 

Vegetable Kingdom. 

Systematic yame 
of the 

ffifjalhts i)3Innts 




inotDcringPlants ] 









Plants witK 
Naked Seeds 



Plants with 
Enclosed Seeds 


1. Prima>val 


2. Green algas 

3. Brown algce 

4. Red algee 

5. Licliena 

6. Fungi 

7. Tangle-mosses 

8. Liverworts 

9. Frondose- 


10. Turf-mosses 

11. Shaft-ferns 

12. Frondose- 


13. Aquatic ferns 

14. Scale-ferns 

15. Palm-ferns 

16. Pines 

1. Archephyceee 


2. Chlorophyceco 


3. Phceophycece 

4. RlwdopJiycece 


5. Lichenes 

6. Fungi 

V. Charohrya, 

8. Thallohrya 


9. Phyllohrya, 


10. Spliagnohrya 

11. Calatnarim 

12. Filices 


13. Rhizocarpece 

14. SelaginecB 

15. Cycadoee 

16. Coni/ercB 

17. Plants with 17. Monocotyloe 
one seed lobe 

18. Plants with 18. Dicotylai 
two seed lobes 



(Flowers with cyrolla) 

(Star-shaped flowers) 

(Flowers with calyx) 

(Two seed-lobed plants) 

(One seed-lobed plants) 


Cycade* (Pines) 



(Plants with enclosed seeds) 

(Plants with naked seeds) Phanerogamx 

(Flowering plants) Ptcridcce 





Frondosos Sphagnacece 

(Leaf-mosses) (Tarf-mosses) 



Hepatuee (Liverworts) 

(Bed Algae) 

(Brown Algse) 

Muscinae (Mosses) 

1 lAchenes 

CMorophycecu (Lichens) 
((ireen Algaa) I 

Algae (Tangles) 

Fungi inophyta 

(Primaeral Plants) 

Vegetable Monera 


such species as the mimite Protococeus, several hundred 
thousands of which occupy a space no larger than a pin's 
head. At the highest stage we marvel at the gigantic 
Macrocysts, which attain a length of from 300 to 400 feet, the 
Jongest of all forms in the vegetable kingdom. It is possible 
that a large portion of the coal has been formed out of Algae. 
If not for these reasons, yet the Algas must excite our 
special attention from the fact that they form the beginning 
of vegetable life, and contain the original forms of aU other 
groups of plants, supposing that our monophyletic hypo- 
thesis of a common origin for aU groups of plants is correct. 
(Compare p. 83.) 

Most people living inland can form but a very imperfect 
idea of this exceedingly interesting branch of the vege- 
table kingdom, because they know only its proportionately 
small and simple representatives living in fresh water. The 
slimy green aquatic filaments and flakes of our pools and 
ditches and springs, the light green slimy coverings of all 
kitids of wood which have for any length of time been in 
contact with water, the yellowish green, frothy, and oozy 
growths of our village ponds, the green filaments resembling 
tufts of hair which occur everywhere in fresh water, stag- 
nant and flowing, are for the most part composed of dif- 
ferent species of Algae. Only those who have visited 
the sea-shore, and wondered at &e immense masses of 
cast-up seaweed, and who, from the rocky coast of the 
Mediterranean, have seen through the clear blue waters the 
beautifully-formed and highly-coloured vegetation of Algas 
at the bottom, know how to estimate the importance of the 
class of Algse. And yet, even these marine Algje-forests 
of EaL-()])ean shores, so rich in forn s, give only a faint idea 


of the colossal forests of Sargasso in the Atlantic ocean, those 
immense banks of Algse, covering a space of about 40,000 
square miles — the same which made Columbus, on his voyage 
of discovery, believe that a continent was near. Similar but 
far more extensive forests of Algsc grew in the primaaval 
ocean, probably in dense masses, and what countless genera- 
tions of these ai-chilithic Algse have died out one after 
another is attested, among other facts, by the vast thickness 
of Silurian alum schists in Sweden, the peculiar composition 
of which proceeds from those masses of submarine Algse. 
According to the recently expressed opinion of Frederick 
Mohr, a geologist of Bonn, even the greater part of our coal 
seams have arisen out of the accumulated dead bodies of the 
Algas forests of the ocean. 

Within the branch of the Algae we distinguish four 
diiferent classes, each of which is again divided into several 
orders and families. These again contain a large number of 
different genera and species. We designate these four 
classes as Primaeval Algae, or Archephycess, Green Algae, or 
Ghlorophyceaa, Brown Algse, or Pli£eophyce£8, and Red Algse, 
or Rhodophyceae. 

The first class of Algse, the PrimcEval Algae (Archephycese), 
might also be called primmval plants, because they contain 
the simplest and most imperfect of all plants, and, among 
them, those most ancient of all vegetable organisms out of 
which aU other plants have originated. To them therefore 
belong those most ancient of all vegetable Monera which 
arose by spontaneous generation in the beginning of the 
Laurentian period Furtlicr, we have to reckon among them 
all those vegetable forms of the simplest organization which 
first developed out of the Monera in the Laurentian period, 


and which possessed the form of a single plastid. At 
first the entire body of one of these small primary plants 
consisted only of a most simple cytod (a plastid -without 
kernel), and afterwards attained the higher form of a 
simple cell, by the separation of a kernel in the plasma. 
(Compare above, vol. i. p. 345.) Even at the present day there 
exist various most simple forms of Algae which have devi- 
ated but little from the original primary plants. Among 
them are the Alg<e of the families Codiolacese, Protococ- 
caceD9, Desmidiacese, Palmellacese, Hydrodictyese, and 
several others. The remarkable group of Phycoehromacese 
(Chroocoecacese and Oscillarinese) might also be comprised 
among them, unless we prefer to consider them as an in- 
dependent tribe of the kingdom Protista. 

The monoplaatic Protophyta — that is, those primary Algae 
formed by a single plastid — are of the greatest interest, 
because the vegetable organism in this case completes its 
whole couise of life as a perfectly simple " individual of the 
first order," either as a cytod without kernel, or as a cell 
containing a kernel 

Among the primary plants consisting of a single cytod a]'e 
the exceedingly remarkable Siphonese, which are of con- 
siderable size, and strangely " mimic" the forms of higher 
plants. Many of the Siphonese attain a size of several 
feet, and resemble an elegant moss (Bryopsis), or in 
some cases a perfect flowering plant with stalks, roots, 
and leaves (Caulerpa) (Fig. 17). Yet the whole of this 
large body, externally so variously dift'^rentiated, consists 
internally of an entirely simple sack, possessing the negative 
characters of a simple cytod. 

These curious Siphoneas, Vaueherise, and Caulerpse show 


blG. 17. — Caulerpa denticulata, a niouoplastic Mphoiietin of the natural 
size. The entire branching primary plant, ■which appears to consist of a 
creeping stalk with fibrous roots and indented leaves, is in reality only a 
single plastid^ and moreover a cytod (without a kernel), not even attaining 
the grade of a cell with nucleus. 

US to how great a degree of elaboration a single cytod, 
althougli a most simple individual of the first order, can 
develop by continuous adaptation to the relations of the 
outer world. Even the single-celled primary plants — which 
are distinguished from the monocytods by possessing a 
kernel — develop into a great variety of exquisite forms by 
adaptation ; this is the case especially with the beautiful 


Desmidiaoice, of which a species of Euastrum is represented 
in Fig. 18 as a specimen. 

Fig. 18. — Euastrnm rota, a single-celled Desmid, mucli enlarged. Tlie 
whole of the star-shaped body of this primaeval plant has the formal value 
of a simple cell. In its centre lies the kernel, and within this the kernel 
corpascle, or speck. 

It is very probable that similar primaeval plants, the 
soft body of which, however, was not capable of being- 
preserved in a fossil state, at one time peopled the Lau- 
rentian primreval sea in great masses and varieties, and in 
a gTeat abundance of forms, without, however, going beyond 
the stage of individuality of a simple plastid. 

The group of Green Tangles (Clilorophyceas), or Green 
Algce (ChloroalgiE), are the second class, and the most closely 
allied to the primaeval group. Like the majority of the 
AjchephycecB, all the ChlorophyceEe are coloured green, and 


by the same colouring matter — the substance called leaf- 
green, or chlorophyll — which colours the leaves of all the 
higher plants. 

To this class belong, besides a great number of low 
marine Algas, most of the Algae of fresh water, the 
common water hair-weeds, or Confervse, the green slime- 
balls, or Gloeosphserse, the bright green water-lettuce, or 
Ulva, which resembles a very thin and long lettuce leaf, 
and also numerous small microscopic alg£^, dense masses of 
which form a light green shiny covering to aU sorts of 
objects lying in water — wood, stones, etc. 

These forms, however, rise above the simple primary Algae 
in the composition and differentiation of their body. As 
the green AlgcB, like the primaeval Alg£e, mostly possess a 
very soft body, they are but rarely capable of being petrified. 
However, it can scarcely be doubted that this class of Algas 
— which was the first to develop out of the preceding 
one — most extensively and variously peopled the fresh and 
salt waters of the earth in early times. 

In the third class, that of the Brown Tangles (Phseo- 
phyceae), or Blade Alga2 (Fucoide«), the branch of the Algse 
attains its highest stage of development, at least in regard 
to size and body. The cliaracteristic colour of the Fucoid 
is more or less dark bro-\vn, sometimes tending more to 
an olive green or yellowish green, sometimes more to a 
browTQish red or black colour. 

Among these are the largest of all Alga3, which are at 

the same time the longest of all plants, namely, the 

colossal giant Algse, amongst which the Macrocystis 

pyrifera, on the coast of California, attains a length of 

■100 feet. Also, among our indigenous Algas, the largest 


forms belong to this group. Especially I may mention 
here the stately sugar-tangle (Laminaria), whose slimy, olive 
green thallus-body, resembling gigantic leaves of from 10 
to 15 feet in length, and from a half to one foot in breadth, 
are thrown up in great masses on the coasts of the North 
and Baltic seas. 

To this class belongs also the bladder-wrack (Fucus 
vesiculosus) common in our seas, whose fork-shaped, 
deeply-cut leaves are kept floating on the water by 
numerous air bladders (as is the case, too, with many 
other brown Algas). The freely floating Sargasso Alga 
(Sargasso bacciferum), which forms the meadows or forests 
of the Sargasso Sea, also belongs to this class. 

Although each individual of these large alga-trees is 
composed of many millions of cells, yet at the beginning 
of its existence it consists, like all higher plants, of a single 
cell — a simple egg. This egg — for example, in the case of 
our common bladder-wrack — is a naked, uncovered cell, and 
as such is so like the naked egg-cells of lower marine 
animals — for example, those of the Medusre — that they 
might easily be mistaken one for another (Fig. 19). 

Fig. 19.— The egg of the common bladder, 
■wrack (Fncas vesiculosus), a eimple naked 
cell, much enlarged. In the centre of the 
naked globule of protoplasm the bright kernel 
is visible. 

It was probably the Fueoide£e, or 
Brown AlgfB, which during the pri- 
mordial period, to a great extent 
constituted the characteristic alga-forests of that immense 
space of time. Their petrified remains, especially those of 

THE EED ALG^. 9 1 

the Silurian period, which have been preserved, can, it is 
true, give us but a faint idea of them, because the material 
of these Algae, like that of most others, is ill-suited for pre- 
servation in a fossil state. As has already been remarked, 
a large portion of coal is perhaps composed of them. 

Less important is the fourth class of Algfe, that of the 
Rose-coloured Algce (Rhodophyceffi), or Red Sea-weeds (Flo- 
ridese). This class, it is true, presents a great number 
of different forms ; but most of them are of much smaller 
size than the Brown Algse. Although they are inferior to 
the latter in perfection and differentiation, they far surj)ass 
them in some other respects. To them belong the most beau- 
tiful and elegant of aU Algje, which on account of the fine 
plumose division of their leaf -like bodies, and also on account 
of their pure and delicate red colour, are among the most 
charming of plants. The characteristic red colour some- 
times appeal's as a deep purple, sometimes as a glowing 
scarlet, sometimes as a delicate rose tint, and may verge 
into violet and bluish purple, or on the other hand into 
brown and green tints of marvellous splendour. Whoever 
has visited one of our sea-coast watering places, must have 
admired the lovely forms of the Floride^e, which are fre- 
quently dried on white paper and offered for sale. 

Most of the Eed Algse are so delicate, that they are quite 
incapable of being petrified ; this is the case with the splendid 
Ptilotes, Plocamia, Delesseria, etc. However, there are in- 
dividual forms, like the Chondria and Sphierococca, which 
possess a harder thallus, often almost as hard as cartilage, 
and of these fossil remains have been preserved^principally 
in the Silurian, Devonian, and Carboniferous strata, and 
later in the oolites. It is probable that this class also had 


an important shai^e in the composition of tlie arcliilithic 
Alga3 flora. 

If we now aofain take into consideration tlie flora of the 
primordial period, which was exclusively formed by the 
group of Algse, we can see that it is not improbable that 
its four subordinate classes had a share in the composition 
of those submarine forests of the prinifeval oceans, similar 
to that which the four tj^pes of vegetation — trees with 
trunks, flowering shrubs, grass, and tender leaf-ferns and 
mosses — at present take in the composition of our recent 
land forests. 

We may suppose that the submarine tree forests of the 
primordial period were formed by the huge Brown Algse, 
or Fucoidese. The many-coloured flowers at the foot of 
these gigantic trees were represented by the gay Red 
AlgES, or Florideaa. The green grass between was formed 
by the hair-like bunches of Green Alg£e, or Chloroalgse. 
Finally, the tender foliage of ferns and mosses, which at 
present cover the ground of our forests, fill the crevices left by 
other plants, and even settle on the trunks of the trees, at 
that time probably had representatives in the moss and fern- 
like Siphoneai, in the Caulerpa and Bryopsis, from among 
the class of the primary Algce, Protophyta, or Archcphycese. 

With regard to the relationships of the different classes of 
Algae to one another and to other plants, it is exceedingly 
probable that the Primary Algge, or Arehephycese, as already 
remarked, form the common root of the pedigree, not merely 
for the different classes of Algte, but for the whole vege- 
table kingdom. On this account they may with justice be 
designated as primaeval plants, or Protophyta. 

Out of the naked vegetable Monera, in the beginning of the 


Laurentian period, enclosed cytods were probably the first to 
arise (vol. i p. 345), by the naked, structureless, albuminous 
substance of the Monera becoming condensed in the form of 
a pellicle on the surface, or by secreting a membrane. At a 
later period, out of these enclosed cytods genuine vegetable 
cells probably arose, as a kernel or nucleus separated itself 
in the interior from the surrounding ceU-substance or 

The three classes of Green Algse, Brown Alga?, and Red 
Algae, are perhaps three distinct classes, which have arisen in- 
dependently of one another out of the common radical group 
of Primseval Algse, and then developed themselves further 
(each according to its kind), and have variously branched 
off into orders and families. The Brown and Red Algae 
possess no close blood relationship to the other classes of the 
vegetable kingdom. These latter have most probably arisen 
out of the Primaeval Algse, either directly or by the inter- 
mediate step of the Green Alg33. 

It is probable that Mosses (out of which, at a later time. 
Ferns developed) proceeded from a group of Green Algaj, 
and that Fungi and Lichens proceeded from a group of 
Primaeval Algee. The Phanerogamia developed at a much 
later period out of Ferns. 

As a second class of the Vegetable Kingdom we have 
above mentioned the Thread-plants (Inophyta). We under- 
stood by this term the two closely related classes of Lichens 
and Fungi. It is possible that these Thallus plants have 
not arisen out of the Primaeval Algae, but out of one or 
more Monera, which, independently of the latter, arose by 
spontaneous generation. It appears conceivable that many 
of the lowest Fungi, as for example, many ferment-causing 


fungi (forms of Microeoecus, etc.), owe their origin to a 
number of different archigonic Monera (that is, Monera 
originating by spontaneous generation). 

In any case the Thread-plants cannot be considered as 
the progenitors of any of the higher vegetable classes. 
Lichens, as weR as fungi, are distinct from the higher 
plants in the composition of their soft , bodies, consisting 
as it does of a dense felt-work of very long, variously 
interwoven, and peculiar threads or chains of cells — the 
so-called hyphoe, on which account we distinguish them 
as a province under the name Thread-plants. From 
their peculiar nature they could not leave any important 
fossil remains, and consequently we can form only a very 
vague guess at their palseontological development. 

The first class of Thread-plants, the Fungi, exhibit a 
very close relationship to the lowest Algse ; the Algo-fungi, 
or Phycomycetes (the Saprolegnise and Peronosporse) in 
reality only differ from the bladder-wracks and SiphoneiB 
(the Vaucheria and Caulerpa) mentioned previously by the 
want of leaf-green, or chlorophyll. But, on the other hand, 
all genuine Fungi have so many peculiarities, and deviate so 
much from other plants, especially in their mode of taking- 
food, that they might be considered as an entirely distinct 
province of the vegetable kingdom. 

Other plants live mostly upon inorganic food, upon simple 
combinations which they render more complicated. They 
produce protoplasm by the combination of water, carbonic 
acid, and ammonia. They take in carbonic acid and give 
out oxygen. But the Fungi, like animals, live upon 
organic food, consisting of complicated combinations of 
carbon, which they receive from other organisms and 


assimilate. They inhale oxygen and "give ont carbonic 
acid like animals. They also never form leaf-green, or 
chlorophyll, which is so characteristic of most other plants. 
In like manner they never produce starch. Hence many 
eminent botanists have repeatedly proposed to remove the 
Fungi completely out of the vegetable kingdom, and to 
regard them as a special and third kingdom, between that 
of animals and plants. By this means our kingdom of Pro- 
tista would be considerably increased. The Fungi in this 
case would, in the first place, be allied to the so-called 
" slime moulds," or Myxomycetes (which, however, never 
form any hyphas). But as many Fungi propagate in a sexual 
manner, and as most botanists, according to the prevalent 
opinion, look upon Fungi as genuiae plants, we shall here 
leave them in the vegetable kingdom, and connect them with 
lichens, to which they are at all events most nearly related. 

The phyletic origin of Fungi will probably long remain 
obscure. The close relationship already hinted at between 
the Phycomycetes and Siphonese (especially between the 
Saprolegni^ and Vaucherise) suggests to us that they are 
derived from the latter. Fungi would then have to be con- 
sidered as Algae, which by adaptation to a parasitical life 
have become very peculiarly transformed. Many facts, 
however, support the supposition that the lowest fungi 
have orio-inated independently from archigonic Monera. 

The second class of Inophyta, the Lichens (Lichenes), are 
very remarkable in relation to phylogeny ; for the surprising 
discoveries of late years have taught us that every Lichen 
is really composed of two distinct plants — of a low form of 
Alfa (Nostochacese, Chroococcaceffi), and of a parasitic form 
of Fungus (Ascomycetes), which lives as a parasite upon 


tlie former^ and upon the nutritive substances prepared by it 
The green cells, containing chlorophyll (gonidia), which are 
found in every lichen, belong to the Alga. But the colourless 
threads (hyphee) ■which, densely interwoven, form the princi- 
pal mass of the body of Lichens, belong to the parasitic 
Fungus. But in all cases the two forms of plants — Fungus 
and Alga — which are always considered as members of two 
quite distinct provinces of the vegetable kingdom, are so 
firmly united, and so thoroughly interwoven, that nearly 
every one looks upon a Lichen as a single organism. 

Most Lichens form small, more or less formless or irreou- 
larly indented, crust-like coverings to stones, bark of trees, 
etc. Their colour varies through all possible tints, from the 
purest white to yellow, red, green, brown, and the deepest 

Many lichens are important in the economy of nature from 
the fact that they can settle in the driest and most barren 
localities, especially on naked rocks upon which no other 
plant can live. The hard black lava, which covers many 
square miles of ground in volcanic regions, and which 
for centuries frequently presents the most determined 
opposition to the life of every kind of vegetation, is always 
first occupied by Lichens. It is the white or grey Lichens 
(Stereocaulon) which, in the most desolate and barren fields 
of lava, always begin to prepare the naked rocky ground 
for cultivation, and conquer it for subsequent higher 
vegetation. Their decaying bodies form the first mould in 
which mosses, ferns, and flowering plants can afterwards 
take firm root. Hardy Lichens are also less afl^eeted by 
the severity of climate than any other plants. Hence the 
naked rocks, even in the highest mountains— for the most 


part covered by eternal snow, on which no plant could 
thrive — are encrusted by the dry bodies of Lichens. 

Leaving now the Fungi, Lichens, and Algae, which are 
comprised under the name of Thallus plants, we enter upon 
the second sub-kingdom of the vegetable kingdom, that of 
the Prothallus plants (ProthaUophyta), which by some 
botanists are called phyllogonic Ciyptogamia (in contradis- 
tinction to the ThaUus plants, or thallogonic Cryptogamia). 
This sub-kingdom comprises tlie two provinces of Mosses 
and Ferns. 

Here we meet with (except in a few of the lowest 
forms) the separation of the vegetable body into two 
different fundamental organs, axial-organs (stem and root) 
and leaves (or lateral organs). In this the Prothallus plants 
resemble the Flowering plants, and hence the two groups 
have recently often been classed together as stemmed plants, 
or Cormophytes. 

But, on the other hand, Mosses and Ferns resemble the 
Thallus plants, in the absence of the development of 
flowers and seeds, and even Linnaeus classed them with 
these, as Cryptogamia, in contradistinction to the plants 
forming seeds ; that is, flowering plants (Anthophyta or 

Under the name of " Prothallus plants " we combiae the 
closely-related Mosses and Ferns, because both exhibit a 
peculiar and characteristic "alternation of generation" in the 
course of their individual development. For every species 
exhibits two difierent generations, of which the one is 
usually called the Proilialliiim,, or Fore-grozvth, the other is 
spoken of as the Cormus, or actual Stem, of the moss or fern. 

The first and origmal generation, the Fore-growth, or Pro- 


thallus, also called Protonema, still remains in that lower 
stage of elaboration manifested throughout life by all Thallus 
plants ; that is to say, stem and leaf-organs have as yet not 
differentiated, and the entire cell-mass of the Fore-growth 
corresponds to a simple thallus. The second and more 
perfect generation of mosses and ferns — the Stem, or Cormus 
— develops a much more highly elaborate body, which has 
differentiated into stalk and leaf (as in the case of flowering- 
plants), except in the lowest mosses, where this generation 
also remains in the lower stage of the thallus. 

With the exception of these latter forms the first generation 
of Mouses and Ferns (the thallus-shaped Fore-growth) always 
jjroduces a second generation with stem and leaves ; the 
latter in its turn produces the thallus of the first generation, 
and so on. Thus, in this case, as in the ordinary cases of 
alternation of generation in animals, the first generation is 
like the third, fifth, etc., the second like the fourth, sixth, 
etc. (Compare vol. i. p. 20G.) 

Of the two main classes of Prothallus plants, the Mosses 
in general are at a much lower stage of development than 
the Ferns, and their lowest forms (especially in an anatomical 
respect) form the transition from the Thallus plants through 
the Algse to Ferns. The genealogical connection of Mosses 
and Ferns which is indicated by this fact can, however, be 
inferred only from the case of the most imperfect forms of 
the two classes ; for the more perfect and higher groups of 
mosses and ferns do not stand in any close relation to one 
another, and develop in completely opposite dii'ectiong. In 
any case Mosses have arisen directly out of ThaUus plants, 
and probably out of Green Algas. 

Ferns, on the other hand, are probably derived from 


extinct unknown Mosses, which were very nearly related 
to the lowest liverworts of the present day. In the 
history of creation, Ferns are of greater importance than 

The branch of Mosses (Museinse, also called Musci, or 
Bryophyta) contains the lower and more imperfect plants of 
the group of Prothallophytes, which as yet do not possess 
vessels. Their bodies are mostly so tender and perishable 
that they are very ill-suited for being preserved in a recog- 
nizable state as fossils. Hence the fossil remains of all 
classes of Mosses are rare and insignificant. It is probable 
that Mosses developed in very early times out of the Thallus 
plants, or, to be more precise, out of the Green Algse, It is 
probable that in the primordial period thei'e existed aquatic 
forms of transition from the latter to Mosses, and in the 
primary period to those living on land. The Mosses of the 
present day — out of the gradually differentiating develop- 
ment of which comparative anatomy may draw some infer- 
ences as to their genealogy — are divided into two different 
classes, namely : (1) Liverworts ; (2) Leafy Mosses. 

The first and oldest class of Mosses, which is directly 
allied to the Green AlgfB, or Conferva3, is formed by the Liver- 
worts (Hepaticee, or Thallobrya). The mosses belonging to 
them are, for the most part, small and insignificant in form, 
and are little known. Their lowest forms still possess, 
in both generations, a simple thallus like the Thallus plants ; 
as for example, the Ricciffi and Marchantiacese. But the 
more highly developed liverworts, the Jungermanniacese 
and those akin to them, gradually commence to differentiate 
stem and leaf, and their most highly-developed forms ai'e 
closely allied to leaf-mosses. By this transitional series 


the liverworts show their direct derivation from the 
Thallophytes, and more especially from the Green Alga3. 

The Mosses, which are generally the only ones known 
to the uninitiated — and which, in fact, form the principal 
portion of the whole branch — belong to the second class, 
or Leafy Mosses (Musci frondosi, called Musci in a narrow 
sense, also Phyllobrya). Among them are most of those 
pretty little plants which, united in dense groups, form 
the bright glossy carpet of moss in our woods, or which, 
in company with liverworts and lichens, cover the bark 
of trees. As reservoirs, carefully storing up moisture, they 
are of the greatest importance in the economy of nature. 
Wherever man mercilessly cuts down and destroys forests, 
there, as a consequence, disappear the leafy mosses which 
covered the bark of the trees, or, protected by their 
shade, clothed the ground, and filled the spaces between 
the larger plants. Together with the leafy mosses dis- 
appear the useful reservoirs which stored up rain and 
dew for times of drought. Thus arises a disastrous dryness 
of the ground, which prevents the growth of any rich 
vegetation. In the greater part of Southern Europe — in 
Greece, Italy, Sicily, and Spain — mosses have been destroyed 
by the inconsiderate extirpation of forests, and the ground 
has thereby been robbed of its most useful stores of 
moisture; once flourishing and rich tracts of land 
have been changed into dry and barren wastes. Un- 
fortunately in Germany, also, this rude barbarism is 
beginning to prevail more and more. It is probable that 
the small frondose mosses have played this exceedingly 
important part in nature for a very long time, possibly 
from the beginning of the primary period But as their 


tender bodies are as little suited as those of aU other 
mosses for being preserved in a fossil" state, palseontology 
can give us no information about this. 

We learn from the science of petrifactions much more 
than we do in the case of Mosses of the importance which 
the second branch of Prothallus plants — that is, Ferns — 
have had in the history of the vegetable w^orld. Ferns, or 

■ more strictly speaking, the " plants of the fern tribe" 
(Filicinese, or Pterideje, also called Pteridophyta, or Vascular 
Cryptogams), formed during an extremely long period, 
namely, during the whole primary or palEeoUthic period, the 
principal portion of the vegetable world, so that we may 
without hesitation caU it the era of Fern Forests. From the 
beginning of the Devonian period, in which organisms 
living on land appeared for the first time, namely, during 
the deposits of the Devonian, Carboniferous, and Pei-mian 
strata, plants like Ferns predominated so much over all 
others, that we are justified in giving this name to that 
period. In the stratifications just mentioned, but above aU, 
in the immense layers of coal of the Carboniferous or coal 
period, we find such numerous and occasionally well pre- 
served remains of Ferns, that we can form a tolerable vivid 
picture of the very peculiar land fiora of the palaeolithic 
period. In the year 1855 the total number of the then 
known paleolithic species of plants amounted to about a 
thousand, and among these there were no less than 872 Ferns. 
Araono' the remaining 128 species were 77 Gymnosperms 
(pines and palm-ferns), 40 ThaUus plants (mostly Algse), and 

i, about 20 not accurately definable Cormophyta (stem-plants). 

■ As already remarked. Ferns probably developed out of the 

lower liverworts in the beginning of the primary period. 


In their organization Ferns rise considerably above Mosses, 
and in their more highly developed forms even approach the 
flowering plants. In Mosses, as in Thallus plants, the entire 
body is composed of almost equi-formal cells, little if at all 
differentiated ; but in the tissues of Ferns we find those 
peculiarly differentiated strings of cells which are called the 
vessels of plants, and which are universally met with in 
flowering plants. Hence Ferns are sometimes united as 
" vascular Cryptogams " with Phanerogams, and the group 
so formed is contrasted as that of the "vascular plants" 
with " cellular plants," — that is, with " cellular cryptogams" 
(Mosses and Thallus plants). This very important process 
in the organization of plants — the formation of vessels 
— flrst occurred, therefore, in the Devonian period, con- 
sequently in the beginning of the second and smaller half 
of the organic history of the earth. 

The branch of Ferns, or Filicinse, is divided into five 
distinct classes : (1) Fro ndose Ferns, or Pteridse ; (2) Reed 
Ferns, or Calamaria ; (3) Aquatic Ferns, or PJiizocarpeae ; 
(4) Snakes Tongues, or Ophioglossa? ; and . (5) Scale Ferns, 
or Lepidophyta. By far the most important of these five 
classes, and also the richest in forms, were first the Frondose 
Ferns, and then the. Scale-ferns, which formed the princi- 
pal portion of the paliEolithic forests. The Reed Ferns, on 
the other hand, had at tliat time already somewhat 
diminished in number ; and of the Aquatic Ferns, we do not 
even know with certainty whether they tlien existed. It is 
diflicult for us to form any idea of the very peculiar 
character of those gloomy palaeolithic fern forests, in which 
the whole of the gay abundance of flowers of our present 
flora was entirely wanting, and which were not enlivened 


by any birds. Of the flowering plants tliere then existed 
only the two lowest classes, the pines and palm ferns, 
with naked seeds, whose simple and insignificant blossoms 
scarcely deserve the name of flowers. 

The phylogeny of Ferns, and of the Gymnosperms which 
have developed out of them, has been made especially clear 
by the excellent investigations which Edward Strasburger 
published in 1872, on "The Coniferae and Gnetacese," as 
also " On AzoUa." This thoughtful naturalist and Charles 
Martins, of Montpellier, are among the few botanists who 
have thoroughly xmderstood the fundamental value of the 
Theory of Descent, and the mechanical-causal connection 
between ontogeny and phylogeny. The majority of 
botanists do not even yet know the important difierence 
between homology and analogy, between the morphological 
and physiological comparison of parts — which has long 
suiee been recognized in zoology — but Strasburger has 
employed this distinction and the principle of evolution in 
his " Comparative Anatomy of the Gymnosperms," in order 
to sketch the outlines of the blood relationship of this 
important group of plants. 

The class among Fems which has developed most directly 
out of the Liverworts is the class of real Ferns, in the 
nan-ow sense of the word, the Frondose Ferns (Filiccs, or 
PhyUopterides, also called Pteridse). In the present flora of 
the temperate zones this class forms only a subordinate 
part, for it is in most cases represented only by low forms 
without trunks. But in the torrid zones, especially in the 
moist, steaming forests of tropical regions, this class presents 
us with the lofty palm-like fern trees. These beautiful tree- 
ferns of the present day, which form the chief ornament of 


our hot-houses, can however give us but a faint idea of 
the stately and splendid fi'ondose ferns of the primary 
period, whose mighty trunks, densely crowded together, 
then formed entire forests. These trunks, accumulated in 
super-incumbent masses, are found in the coal seams of the 
Carboniferous period, and between them, in an excellent 
state of preservation, are found the impressions of the 
elegant fan-shaped leaves, crowning the top of the trunk in 
an umbrella-like bush. The varied outlines and tlie feather- 
like forms of these fronds, the elegant shape of the 
branching veins or bunches of vessels in their tender foliage, 
can still be as distinctly recognized in the impressions of the 
palisolithic fronds as in the fronds of ferns of the present 
day. In many cases even the clusters of fruit, which are 
distributed on the lower surface of the fronds, are distinctly 
preserved. After the carboniferous period, the predominance 
of frondose ferns diminished, and towards the end of the 
secondary period they played almost as subordinate a part 
as they do at the present time. 

The Calamarife, Ophioglossse, and Rhizocarpeee seem to 
have developed as three diverging branches out of the 
Frondose Ferns, or Pteridje. The Calamarise, or Calamophyta, 
have remained at the lowest level among these three classes. 
The Calamariss comprise three different orders, of which 
only one now exists, namely, the Horse-tails (Equisetacece). 
The two other orders, the Giant Reeds (Calamitese), and the 
Star-leaf Reeds (Asterophylliteae), are long since extinct. 
All CalamarijB are characterized by a hollow and jointed 
stalk, stem, or trunk, upon which the branches and leaves 
(in cases M^here they exist) are set so as to encircle the 
jointed stem in whorls. The hollow joints of the stalk are 


separated from one another by partition walls. In Horse- 
tails and Calamiteas the surface is traversed by longitudinal 
ribs running parallel, as in the case of a fluted column, and 
the outer skin contains so much silicious earth in the living 
forms, that it is used for cleansing and polishing. In 
the Asterophyllitese, the star-shaped whorls of leaves were 
more strongly developed than in the two other orders. 
There exist, at present, of the Calamarije only the in- 
significant Horse-tails (Equisetum), which grow in marshes 
and on moors; but during the whole of the primary 
and secondary periods they were represented by great trees 
of the genus Equisetites. There existed, at the same time, 
the closely related order of the Giant Reeds (Calamites), 
whose strong trunks grew to a height of about fifty feet. 
The order of the AsterophyUites, on the other hand, con- 
tained smaller and prettier plants, of a very peculiar form, 
and belongs exclusively to the primary period. 

Among all Ferns, the history of the third class, that of 
the Root, or Aquatic Ferns (Rhizorcarpe83, or Hydropterid^), 
is least known to us. In their structure these ferns, which 
live in fresh water, are on the one hand allied to the frond 
ferns, and on the other to the scaly ferns, but they are more 
closely related to the latter. Among them are the but 
little known moss ferns (Salvinia), clover ferns (Marsilea), 
and piU ferns (Pilularia) of our fresh waters ; further, the 
large AzoUa which floats in tropical ponds. Most of the 
aquatic ferns are of a delicate nature, and hence ill-suited 
for being petrified. This is probably the reason of their 
fossil remains being so scarce, and of the oldest of those 
known to us having been found in the Jura system. It is 
probable, however, that the class is much older, and that it 


was already developed during tlie palasolithic period out of 
other ferns by adaiotation to an aquatic life. 

The fourth class of ferns is formed by the Tongue Ferns 
(Ophioglossse, or Glossopterides). These ferns, to which 
belongs the Botrychium, as well as the Ophioglossum 
(adder's-tongue) of our native genera, were formerly con- 
sidered as forming but a small subdivision of the frondose 
ferns. But they deserve to form a special class, because 
they represent important transitional forms from the 
Pterideee and Lepidophytes towards higher plants, and 
must be regarded as among the direct progenitors of the 
flowering plants. 

The fifth and last class is formed by the Scale Ferns 
(Lepidophytes, or Selagines). In the same way as the 
Ophioglossae arose out of the frondose forms, the scale ferns 
arose out of the Ophioglossse. They were more highly 
developed than all other ferns, and form the transition to 
flowering plants, which must have developed out of them. 
Next to the frondose ferns they took the lai'gest part in the 
composition of the palaeolithic fern forests. This class also 
contains, as does the class of reed ferns, three nearly related 
but still very difierent orders, of which only one now exists, 
the two others having become extinct towards the end of 
tlie carboniferous period. The scaled ferns still existing 
belong to the order of the club-mosses (Lycopodiacese). 
They are mostly small, pretty moss-like plants, whose 
tender, many -branched stalk creeps in curves on the ground 
like a snake, and is densely encompassed and covered by 
small scaly leaves. The pretty creeping Lycopodium of 
our woods, which mountain tourists twine round their 
hats, is known to all, as also the still more delicate 


Selaginella, which under the name of creeping moss is used 
to adorn the soil of our hot-houses in the form of a thick 
carpet. The largest club-mosses of the present day are found 
in the Sunda Islands, where their stalks rise to the height 
of twenty-five feet, and attain half a foot in thickness. 
But in the primary and secondary periods even larger trees 
of this kind were widely distributed, the most ancient of 
which probably were the progenitors of the pines 
(Lycopodites). The most important dimensions were, how- 
ever, attained by the class of scale trees (Lepidodendreae), 
and by the seal trees (Sigillariese). These two orders, with 
a few species, appear in the Devonian period, but do not 
attain their immense and astonishing development until the 
Carboniferous period, and become extinct towards the end 
of it, or in the Permian period directly following upon it. 
The scale trees, or Lepidodendrese, were probably more 
closely related to club-mosses than to Sigillariese. They 
grew into splendid, straight, unbranching trunks which 
divided at the top into numerous forked branches. They 
bore a large crown of scaly leaves, and like the trunk were 
marked in elegant spiral lines by the scars left at the base 
of the leaf stalks which had fallen off We know of scale- 
marked trees from forty to sixty feet in length, and from 
twelve to fifteen feet in diameter at the root. Some trunks 
are said to be even more than a hundred feet in length. In 
the coal are found stUl larger accumulations of the no less 
highly developed but more slender tninks of the remarkable 
seal trees, Sigillariese, which in many places form the princi- 
pal part of coal seams. Their roots were formerly described 
as quite a distinct vegetable form (under the name of 
Stigmaria). The Sigillariese are in many respects veiy like 


the scale-trees, but differ from them and from ferns in 
general in many ways. They were possibly closely related 
to the extinct Devonian Lycopteridece, combining character- 
istic peculiarities of the club-mosses and the frondose ferns, 
which Strasburger considers as the hypothetical primary 
form of flowering plants. 

In leaving the dense forests of the primary period, which 
were principally composed of frond ferns (Lepidodendrese 
and Sigillarieffi), we pass onwards to the no less character- 
istic pine forests of the secondary period. Thus we leave 
the domain .of the Cryptogamia, the plants forming neither 
flowers nor seeds, and enter the second main division of the 
vegetable kingdom, namely, the sub-kingdom of the Phanero- 
gamia, flowering plants forming seeds. This division, so rich 
in forms, containing the principal portion of the present 
vegetable world, and especially the majority of plants living 
on land, is certainly of a much more recent date than the 
division of Cryptogamia. For it can have developed out 
of the latter only in the course of the palaeolithic period. 
We can with full assurance maintain that, during the whole 
archilithic period, hence during the first and longer half of 
the organic history of the earth, no flowering plants as yet 
existed, and that they first developed during the primary 
period out of Cryptogamia of the fern kind. The anatomical 
and embryological relation of Phanerogamia to the latter 
is so close, that from it we can with certainty, infer their 
genealogical connection, that is, their true blood relation- 
ship. Flowering plants cannot have directly arisen out of 
thallus plants, nor out of mosses ; but only out of ferns, or 
Filicines. Most probably the scaled ferns, or Lepidophyta, 
and more especially amongst these the Lycopodiace?e, forms 


closely related to the Selaginella of the present day, have 
been the direct progenitors of the Phanerogamia. 

On account of its anatomical structure and its embryo- 
logical development, the sub-kingdom of the Phanerogamia 
has for a long time been divided into two large branches, 
into the Gymnosperyns, or plants with naked seeds, and the 
Angiosperms, or plants with enclosed seedsi The latter are 
in every respect more perfect and more highly organized 
than the former, and developed out of them only at a late 
date during the secondary period. The Gymnosperms, both 
anatomically and embryologically, form the transition group 
from Ferns to Angiosperms. 

The lower, more imperfect, and the older of the two main 
classes of flowering plants, that of the Archispermece, or 
Gymnosperms (with naked seeds), attained its most varied 
development and widest distribution during the mesolithic 
or secondary epoch. It was no less characteristic of this 
period, than was the fern group of the preceding primary, 
and the Angiosperms of the succeeding tertiary, epoch. 
Hence we might call the secondary epoch that of Gymno- 
sperms, or after its most important representatives, the era 
of Pine Forests. The Gymnosperms are divided into three 
classes: the Coniferae, Cycadeje, and Gnetaeeffi. We find 
fossil remains of the pines, or Conifers, and of the Cycads, 
even in coal, and must infer from this that the transition 
from scaled ferns to Gymnosperms took place during the 
Coal, or possibly even in the Devonian period. However, 
the Gymnosperms play but a very subordinate part during 
the whole of the primary epoch, and do not predominate 
over Ferns until the beginning of the secondary epoch. 

Of the two cla-sses of Gymnosperms just mentioned, that 


of the Palm Ferns (Zamise, or Cycacle?e) stands at the lowest 
stage, and is directly allied to ferns, as the name implies, 
so that some botanists have actually included them 
in the fern group. In their external form they resemble 
palms, as ■well as tree ferns (or tree-like frond ferns), and 
are adorned by a crown of feathery leaves, which is placed 
either on a thick, short trunk, or on a slender, simple 
trunk ]ike a pillar. At the present day this class, once so 
rich in forms, is but scantily represented by a few forms 
living in the torrid zones, namely, by the coniferous 
ferns (Zamia), the thick-trunkcd bread-tree (Encephalartos), 
and the slender-trunked Caffir bread-tree (Cycas). They 
may frequently be seen in hot-houses, and are generally 
mistaken for palms. A much greater variety of forms than 
occui's among the still existing palm ferns (Cycadese) is pre- 
sented by the extinct and fossil Cycads, which occurred in 
great numbers more towards the middle of the secondary 
period, during the Jura, and which at that time princiiDally 
determined the character of the forests. 

The class of Pines, or coniferous trees (Coniferse), has pre- 
served down to our day a greater variety of forms than have 
the palm ferns. Even at the present time the trees belonging 
to it — cypresses, juniper trees, and trees of life (Thuja), the 
box and ginko trees (Salisburya), the araucarla and cedars, 
but above all the genus Pinus, which is> so rich in forms, 
with its numerous and important species, sprvices, pines, firs, 
larches, etc. — still play a very important part in the most 
different parts of the earth, and almost of themselves consti- 
tute extensive forests. Yet this development of pines seems 
but weak in comparison with the predominance which the 
class had attained over other plants during the early 


secondary period, that of the Trias. At that time mighty 
coniferous trees — with but proportionately few genera and 
species, but standing together in immense masses of indivi- 
duals — formed the principal part of the mesolithic forests. 
This fact justifies us ia calling the secondary period the 
" era of the pine forests," although the remains of Cycadeffi 
predominate over those of coniferous trees in the Jura 

From the pine forests of the mesolithic, or secondary 
period, we pass on into the leafy forests of the cffinolithic, or 
tertiary period, and we arrive thus at the consideration of 
the sixth and last class of the vegetable kingdom, that of 
the Metaspermce, Angiospermce, or plants ivith enclosed 
seeds. The first certain and undoubted fossils of plants 
with enclosed seeds are found in the strata of the chalk 
system, and indeed Ave here find, side by side, remains of the 
two classes into which the main class of Angiosperms is 
generally divided, namely, the one seed-lohed plants, or 
nnonocotylcB, and the two seed-lohed plants, or dicotyloi. 
However, the whole gToup probably originated at an earlier 
period during the Trias. For we know of a number of 
doubtful and not accurately definable fossil remains of 
plants from the Oolitic and Trias (sic) periods, which some 
botanists consider to be Monocotylse, whilst others consider 
them as Gymnosperms. In regard to the two classes of 

* The primary stock of the Coniferse divided into two branches at an early 
period, into the Araticarice on the one hand, and the Taxaceas, or yew-trees, 
on the other. The majority of recent Coniferse are derived from the former, 
Ont of the latter the third class of the Gymnosperms — the Meninges, or 
Gnetaceoe — were developed. This small bnt very interesting class contains 
only three different genera — Gnetum, Welwitschia, and Kphodra ; it is, 
however, of great importance, as it forms the transition groap from the 
Coniferaa to the Angiosiierms, and more especially to the Dicotyledons. 


plants with enclosed seeds, the Monocotylse and Dicotylse, 
it is exceedingly probable that the Dicotyledons developed 
out of the GnetacetE, but that the Monocotyledons developed 
later out of a branch of the dicotyledons. 

The class of one seed-lobed plants (Monocotylte, or 
Monocotyledons, also called Endogenas) comprises those 
flowering plants whose seeds possess but one germ leaf or 
seed lobe (cotyledon). Each whorl of its flower contains 
in most cases tho^ee leaves, and it is very probable that the 
mother plants of all Monocotyledons possessed a regular 
triple blossom. The leaves are mostly simple, and traversed 
by sifuple, straight bunches of vessels or " nerves." To this 
class belong the extensive families of the rushes, gi-asses, 
lilies, irids, and orchids, further a number of indigenous 
aquatic plants, the water-onions, sea grasses, etc., and 
finally the splendid and higlily developed families of the 
Aroidese and Pandanea;, the bananas and palms. On the 
whole, the class of Monocotyledons — in spite of the great 
variety of forms which it developed, both in the tertiary 
and the present period — is much more simply organized 
than the class of the Dicotyledons, and its history of 
development also ofl"ers much less of interest. As their 
fossil remains are for the most part difiicult to recognize, 
it still remains at present an open question in vi'hich 
of the three great secondary periods— the Trias, Jara, 
or chalk period — the Monocotyledons originated. At all 
events they existed in the chalk period as surely as did the 

The second class of plants with enclosed seeds, the tiuo 
seed-lohed (Dicotylas, or Dicotyledons, also called Exogenas) 
presents much greater historical and anatomical interest in 

Eaeckel- History of Oeatiorv. 

jyiain Divisions 
of the 

Tlowerless Plants , Cryptogamae 

TtallTLsplants, ThalloplrTta. 



Terns, Pilicinae . 


Plover Plants, Phanerogamae. 

ITaked seeded. 

Cover- seeded, .Angiospermae. 

Total 100. 

Single-stemmed or 


of tlie 




the development of its subordinate groups. The flowering 
plants of this class generally possess, as their name indicates, 
two seed lobes or germ leaves (cotyledons). The number of 
leaves composing its blossom is generally not three, as in 
most Monocotyledons, but four, five, or a multiple of those 
numbers. Their leaves, moreover, are generally raore highly 
differentiated and more composite than those of the Mono- 
cotyledons; they are traversed by crooked, branching 
bunches of vessels or " veins." To this class belong most of 
the leafed trees, and as they predominate in the tertiary 
period as well as, at present, over the Gymnosperms and 
Ferns, we may call the cjenolithic period that of leafed 

Although the majority of Dicotyledons belong to the most 
highly developed and most perfect plants, still the lowest 
division of them is directly allied to the Gymnosperms, and 
particularly to the Gnetacese. In the lower Dicotyledons, as 
in the case of the Monocotyledons, calyx and corolla are as 
yet not differentiated. Hence they are called Apetalous 
(Monochlamydea?, or Apetate). This sub-class must there- 
fore doubtless be looked upon as the original group of the 
Angiosperms, and existed probably even during the Trias 
and Jura periods. Among them are most of the leafed trees 
bearing catkins — ^birches and alders, willows and poplars, 
beeches and oaks; further, the plants of the nettle kind 
— nettles, hemp, and hops, figs, mulberries, and elms ; finally, 
plants like the spurges, laurels, and amarantL 

It was not until the chalk period that the second and 

more perfect class of the Dicotyledons appeared, namely, 

the group with corollas (Dichlamydeae, or Corolliflorse). 

These arose out of the Apetalte from the simple cover of the 



blossoms of the latter becoming differentiated into caljrs and 
corolla. The sub-class of the CoroUiflorje is again divided 
into two large main divisions or legions, each of which 
contains a large number of different orders, families, genera, 
and species. The first legion bears the name of star-flowers, or 
Diapetalse, the second that of the beU-flowers, or Gamopetalse. 

The lower and less perfect of the two legions of the 
OoroUiflorse are the star-flowers (also called Diapetalse or 
Dialypetalae). To them^ belong the extensive families of the 
TJmbeUifera3, or umbrella-worts (wild carrot, etc.), the Cruci- 
feraj, or cruciform blossoms (cabbage, etc.) ; further, the 
Ranuneulaceoe (buttercups) and Crassulaceas, the MaUows 
and Geraniums, and, besides many others, the large group of 
Roses (which comprise, besides roses, most of our fruit trees), 
and the Pea-blossoms (containing, among others, beans, clover, 
genista, acacia, and mimosa). In all these Diapetalse the 
blossom-leaves remain separate, and never grow together, 
as is the case in the Gamopetalge. These latter developed 
first in the tertiary period out of the Diapetalse, whereas the 
Diapetalse appeared in the chalk period together with the 

The highest and most perfect group of the vegetable 
kingdom is formed by the second division of the OoroUiflorse, 
namely, the legion of bell-flowers (Gamopetalse, also called 
Monopetalse or Sympetalffi). In this group the blossom- 
leaves, which in other plants generally remain separate, 
grow regularly together into a more or less bell-Uke, funnel- 
shaped, or tubular flower. To them belong, among others, 
the BeU-flowers and Convolvulus, Primroses and Heaths, 
Gentian and Honeysuckle, further the family of the Olives 
(olive trees, privet, elder, and ash), and finally, besides many 


other families, the extensive division of the Lip-blossoms 
(Labiatse) and the Composites. In these last the differen- 
tiation and perfection of the Phanerogamic blossoms attain 
their highest stage of development, and we must therefore 
place them at the head of the vegetable kingdom, as the 
most perfect of aU plants. In accordance with this, the 
legion of the Gamopetalse appear ia the organic history of 
the earth later than all the main groups of the vegetable 
kingdom — in fact, not until the cjenolithic or tertiary epoch. 
In the earliest tertiary period the legion is still very rare, 
but it gradually increases in the mid-tertiary, and attains its 
fuU development only in. the latest tertiary and the qua- 
ternary period. 

Now if, having reached our own time, we look back upon 
the tuhole history of the development of the vegetable 
Idngdom, we cannot but perceive in it a grand confirmation 
of the Theory of Descent. The two great principles of organic 
development which have been pointed out as the necessary 
results of natural selection in the Struggle for Life, namely, 
the laws of differentiation and ^perfecting, manifest them- 
selves everywhere in the development of the larger and 
smaller groups of the natural system of plants. In each 
laro-er or smaller period of the organic history of the earth, 
the vegetable kingdom Increases both in variety and perfec- 
tion, as a glance at Plate IV. will clearly show. During 
the whole of the long primordial period there existed only 
the lowest and most imperfect group, that of the Algse. To 
these are added, in the primary period, the higher and more 
perfect Cryptogamia, especially the main-class of Ferns. 
During the coal period the Phanerogamia begin to develop 
out of the latter; at first, however, they are represented only 


by the lower main-class, that of Gymnosperms. It was not 
until the secondary period that the higher main-class, that of 
Angiospcrms, arose out of them. Of these also there existed 
at fh-st only the lower groups without distinct corollas, the 
Monocotyledons and the Apetalee. It was not until the 
chalk period that the higher Corolliflorse developed out of 
the latter. But even this most highly developed group is 
represented, in the chalk period, only by the lower stage of 
Star-flowers, or Diapetalse, and only at quite a late date, 
in the tertiary period, did the more highly developed Bell- 
blossoms, Gamopetalse, arise out of them, which at the same 
time are the most perfect of aU flowering plants. Thus, in 
each succeeding later division of the organic history of the 
earth the vegetable kingdom gradually rose to a higher 
degree of perfection and variety. 


I. Animal-Plants and Wobms. 

The Natural System of the Animal Kingdom.— Linn sens and Lamarck's 
Systems.— The Pour Types of Bar and Cuvier.— Their Increase to Seven 
Types.— Genealogical Importance of the Seven Types as Independent 
Tribes of the Animal Kingdom. — Derivation of Zoophytes and Worms 
from Primajval Animals. — Monophyletio and Polyphyletic Hypothesis 
of the Descent of the Animal Kingdom. — Common Origin of the Four 
Higher Animal Tribes ont of the Worm Tribe. — Division of the Seven 
Animal Tribes into Sixteen Main Classes, and Thirty-eight Classes. — Pri. 
mseval Animals (Monera, Amcebse, Synamoebas), Gregarinea, Infusoria, 
Plauseades, and Gaatrseades (Plannia and Gastrula). — Tribeof Zoophytes. 
— Spongise (Mucous Sponges, Fibrous Sponges, Calcarcoa? Sponges). — 
Sea Nettles, or Aoalephae Corals, Hood-jelUes, Comb-jeilies). — Tribe of 

The natural system of organisms which we must employ 
in the animal as well as in the vegetable kingdom, as a 
guide in our genealogical investigations, is in both cases 
of but recent origin, and essentially determined by the 
progress of comparative anatomy and ontogeny (the history 
of individual development) during the present century. 
Almost all the attempts at classification made in the last 
century followed the path of the artificial system, which 
was first established in a consistent manner by Charles 


Linnseus. The artificial system differs essentially from the 
natural one, in the fact that it does not make the whole 
organization and the internal structure (depending upon the 
blood relationshijj) the basis of classification, but only 
employs individual, and for the most part external, charac- 
teristics, ■which readily strike the eye. Thus Linnffius dis- 
tinguished his twenty -four classes of the vegetable kingdom 
principally by the number, formation, and combination of 
the stamens. In like manner he distinguished sis classes 
in the animal kingdom principally by the nature of the 
heart and blood. These six classes were : (1) Mammals ; 
(2) Birds ; (3) Amphibious Animals ; (4) Fishes ; (5) Insects ; 
and (6) Worms. 

But these six animal classes of Linnseus are by no means 
of equal value, and it was an important advance when, at 
the end of the last century, Lamarck comprised the first 
four classes as vertebrate animals (Vertebrata), and put them 
in contrast with the remaining animals (the insects and 
worms of Linnasus), of which he made a second main division 
—the invertebrate animals (In vertebrata). In reality Lamarck 
thus agreed with Aristotle, the father of Natural History, 
who had distinguished these two main groups, and called 
the former blood-hearing animals, the latter bloodless 

The next important progress towards a natural system of 
the animal kingdom was made some decades later by two 
most illustrious zoologists, Carl Ernst Bar and George Cuvier. 
As has already been remarked, they established, almost 
simultaneously and independently of one another, the pro- 
position that it was necessary to distinguish several com- 
pletely distinct main groups in the animal kingdom, each of 


which possessed an entirely peculiar type or structure (com- 
pare above, vol. i. p. 53). In each of these main divisions 
there is a tree-shaped and branching gradation from most 
simple and imperfect forms to those which are exceedingly 
composite and highly developed. The degree of development 
within each type is quite independent of the peculiar plan 
of structure, which forms the basis of the type and gives it 
a special characteristic. The " type " is determined by the 
peculiar relations in position of the most important parts of 
the body, and the manner in which the organs are connected. 
The degree of development, however, is dependent upon the 
greater or less division of labour among organs, and on the 
differentiation of the plastids and organs. This extremely 
important and fruitful idea was established by Bar, who 
relied more distinctly and thoroughly upon the history of 
individual development than did Cuvier. Cuvier based 
his argument upon the results of comparative anatomy. 
But neither of them recognized the true cause of the re- 
markable relationships pointed out by them, which is first 
revealed to us by the Theory of Descent. It shows us that 
the common type or plan of structure is determined by iw- 
heritance, and the degree of development or diflferentiation 
by adaptation. (Gen. Morph. ii. 10). 

Both Bar and Cuvier distinguished four different types in 
the animal kingdom, and divided it accordingly into four 
gi-eat main divisions (branches or circles). The fu'st of these 
is formed by the vertebrate animals (Vertebrata), and 
comprises Linnseus' first four classes — mammals, birds, 
amphibious animals, and fishes. The second type is formed 
by the articulated animals (Articulata), containing Linnseus' 
insects, consequently the six-legged insects, and also the 


myriopods, spiders, and Crustacea, but besides these, a large 
number of the worms, especially the ringed worms. The 
third main division comprises the molluscous animals 
(Mollusca) — slugs, snails, mussels, and some kindred groups. 
Finally, the fourth and last circle of the animal kingdom 
comprises the various radiated animals (Radiata), which at 
first sight differ from the three preceding typos by their 
radiated, flower-like form of body. For while the bodies of 
moUuscs, articulated animals, and vertebrated animals consist 
of two symmetrical lateral halves — of two counterparts or 
antimera, of which the one is the mirror of the other — the 
bodies of the so-called radiated animals are composed of 
more than two, generally of four, five, or six counterparts 
grouped round a common central axis, as in the case of a 
flower. However striking this difierence may seem at first, 
it is, in reahty, a very subordinate one, and the radial form 
has by no means the same importance in all " radiated 

The establishment of these natural main groups or types of 
the animal kingdom by Bar and Cuvier was the greatest 
advance in the classification of animals since the time of 
Linnajus. The three groups of vertebrated animals, articu- 
lated animals, and moUuscs are so much in accordance with 
nature that they are retained, even at the present day, little 
altered in extent. But a more accurate knowledge soon 
showed the utterly unnatural character of the group of the 
radiated animals. Leuckart, in 1848, first pointed out that 
two perfectly distinct types were confounded under the 
name, namely, the Star-fishes (Echinoderma) — the sea-stars, 
lily encrinites, sea-urchins, and sea-cucumbers ; and, on the 
other hand, the Animal-plants, or Zoophytes (Coelenterata, 


or Zoopliyta) — the sponges, corals, liood-jelHes, and comb- 
jellies. At the same time, Siebold united the Infusoria with 
the Rhizopoda, under the name of Protozoa (lowest animals), 
into a special main division of the animal kingdom. By 
this the number of animal types was increased to six. It 
was finally increased to seven by the fact that modern 
zoologists separated the main division of the articulated 
animals into two groups : (a) those possessing articulated 
feet (Arthropoda), corresponding to Linnasus' Insects, 
namely, the Flies (with six legs), Myriopods, Spiders, and 
Crustacea ; and (h) the footless Worms (Vermes), or those 
possessing non-articulated feet. These latter comprise only 
the real or genuine Worms (ring-worms, round worms, 
planarian w^ornis, etc.), and therefore in no way correspond 
with the Worms of Linnseus, who had included the molluscs, 
the radiates, and many other lower animals under this name. 

Thus, according to the views of modern zoologists, which 
are given in all recent manuals and treatises on zoology, 
the animal kingdom is composed of seven completely distinct 
main divisions or types, each of which is distinguished by a 
characteristic plan of structure peculiar to it, and perfectly 
distinct from every one of the others. In the natural system 
of the animal kingdom — ^which I shall now proceed to explain 
as its probable pedigree — I shall on the whole agree with 
this usual division, but not without some modifications, which 
I consider very important in connection with genealogy, 
and which are rendered absolutely necessary in consequence 
of our view as to the history of the development of animals. 

We evidently obtain the greatest amount of information 
concerning the pedigree of the animal kingdom (as well as 
concerning that of the vegetable kingdom) from comparative 


anatomy and ontogeny. Besides these, palasontology also 
throws much valuable light upon the historical succession of 
many of the groups. From numerous facts in comparative 
anatomy, we may, in the first place, infer the common origin 
of all tlwse animals which belong to one of the seven " types." 
For in spite of aU the variety in the external form developed 
within each of these types, the essential relative position 
of the parts of the body which determines the type, is 
so constant, and agrees so completely in aU the members 
of every type, that on account of their relations of form 
alone we are obliged to unite them, in the natural system, 
into a single main group. But we must certainly conclude, 
moreover, that this conjunction also has its expression in 
the pedigree of the animal kingdom. For the true cause 
of the intimate agreement in structure can only be the 
actual blood relationship. Hence we may, without further 
discussion, lay down the important proposition that all 
animals belonging to one and the same circle or type must 
be descended from one and the same original primary form. 
In other words, the idea of the circle or type, as it is 
employed in zoology since Bar and Cuvier's time to 
designate the few principal main groups or " sub-kingdoms " 
of the animal kingdoms, coincides with the idea of " tribe " 
or " phylum," as employed by the Theory of Descent. 

If, then, we can trace all the varieties of animal forms to 
these seven fundamental forms, the following question next 
presents itself to us as a second phylogenetic problem — 
Wliere do these seven animal tribes come from ? Are they 
seven original primary forms of an entu-ely independent 
origin, or are they also distantly related by blood to one 
another ? 

TJaueckel-Histary ofCreatUm,. 




At first we might be inclined to answer tliis question in a 
polyphyletic sense, by saying that we must assume, for each 
of the seven great animal tribes, at least one independent 
primary form completely distinct from the others. On 
further considering this difficult problem, we arrive in the 
end at the notion of a monophyletic origin of the aidmal 
kingdom, viz., that these seven primary forms are connected 
at their lowest roots, and that they are derived from a single, 
common primaeval form. In the animal as well as in the 
vegetable kingdom, when closely and accurately considered, 
tJis m,onophyletic hypothesis of descent is found to be 7)%ore 
satisfactory than the polyphyletic hypothesis. 

It is comparative ontogeny (embryology) which first and 
foremost leads to the assumption of the monophyletic origin of 
the whole animal kingdom (the Protista excepted of course). 
The zoologist who has thoughtfully compared the history of 
the individual development of various animals, and has 
understood the importance of the biogenetic principle (p. 33), 
cannot but be convinced that a common root must be 
assumed for the seven different animal tribes, and that all 
animals, including man, are derived from a single, common 
primary form. The result of the consideration of the facts 
of embryology, or ontogeny, is the following genealogical 
or phylogenetic hypothesis, which I have put forward and 
explained in detail in my " Philosophy of Calcareous 
Sponges" (Monograph of the Calcareous Sponges, vol. i. 
pp. 464, 465, etc., — "the Theory of the Layers of the 
Embryo, and the Pedigree of Animals.") 

The first stage of organic life in the Animal kingdom (as in 
the Vegetable and Protista kingdoms) was formed by per- 
fectly simple Monera, originating by spontaneous generation. 


The former existence of this simplest animal form is, even at 
present, attested by the fact that the egg-cell of many 
animals loses its kernel directly after becoming fructified, 
and thus relapses to the lower stage of development of a 
cytod without a kernel, like a Moneron. This remarkable 
occurrence I have interpreted, according to the law of latent 
inheritance (vol. i. p. 205), as a phylogenetic 7'elapse of the 
cellular form into the original form of a cytod. The 
Monerula, as we may caU this egg-cytod without a kernel, 
repeats then, according to the biogenetic principle (vol ii. p. 
33), the most ancient of all animal forms, the common pri- 
mary form of the animal kingdom, namely, the Moneron, 

The second ontogenetic process consists in a new kernel 
being formed in the Monerula, or egg-cytod, which thus 
returns again to the value of a true egg-cell. According to 
this, we must look upon the simple animal cell, containing a 
kernel, or the single-celled primajval animal — which may 
still be seen in a living state in the Aonaibce of the present 
day — as the second step in the series of phylogenetic forms 
of the animal kingdom. Like the still living simple 
Amoebss, and like the naked egg-cells of many lower 
animals (for example, of Sponges and Medusse, etc.), which 
cannot be distinguished from them, the remote phyletic 
primary Amoebse also were perfectly simple naked-cells, 
which moved about in the Laurentian primseval ocean, 
creeping by means of the ever-changing processes of their 
body-substance, and nourishing and propagating themselves 
in the same way as the AmoehaB of the present day. (Com- 
pare vol. i. p. 188, and vol. ii. p. 54) The existence of this 
Amoeba-like, single-celled primary form of the whole animal 
kingdom is unmistakably indicated by the exceedingly im- 


portant fact that the egg of all animals, from those of sponges 
and worms up to those of the ant and man, is a simple cell 

Thirdly, from the " single-cell " state arose the simplest 
multicellular state, namely, a heap or a small community of 
simple, equiformal, and equivalent cells. Even at the present 
day, in the ontogenetic development of every animal egg- 
cell, there first arises a globular heap of equiformal naked 
cells, by the repeated self-division of the primary cell. (Com- 
pare vol. i. p. 190 and the Frontispiece, Fig. 3.) We called 
this accumulation of cells the Tnulherry state (Morula), 
because it resembles a mulbeiTy or blackberry. This Morula- 
body occurs in the same simple foim in all the different 
tribes of animals, and on account of this most important 
circumstance we may infer — according to the biogenetic 
principle — that the Tnost ancient, many-celled, primary form 
of the anim,al kingdom resembled a Morula like this, and 
was in fact a simple heap of Amoeba-like primsBval cells, 
one similar to the other. We shall caU this most ancient 
community of Amoebae — this most simple accumulation of 
animal cells — which is recapitulated in individual develop- 
ment by the Morula — the Synamoeha. 

Out of the Synamcebse, in the early Laurentian period, 
there afterwards developed a fourth primary form of the 
animal kingdom, which we shall call the ciliated germ 
(PlauEea). This arose out of the Synamoeba by the outer 
cells on the surface of the cellular community beginning to 
extend vibrating fringes called cilia, and becoming " cUiated 
cells," and thus differentiating from the inner and unchanged 
cells. The Synamoebce consisted of comi^letely equi- 
formed and naked cells, and crept about slowly, at the 
bottom of the Laurentian primaeval ocean, by means 


of movements like those of an Amoeba. The Plansea, 
on the other hand, consisted of two kinds of different 
cells — inner ones like the AmoebEe, and external " ciliated 
cells." By the vibrating movements of the cilia the entire 
multicellular body acquired a more rapid and stronger 
motion, and passed over from the creeping to the swim- 
ming mode of locomotion. In exactly the same manner 
the Morula, in the ontogenesis of lower animals, still 
changes into a ciHated form of larva, which has been 
known, since the year 1847, under the name of Planula. 
This Planula is sometimes a globular, sometim^es an oval 
body, which swims about in the water by means of a 
vibrating movement ; the fringed (ciliated) and smaller cells 
of the surface differ from the larger inner cells, which 
are unfringed. (Fig. 4 of the Frontispiece.) 

Out of this Planula, or fringed larva, there then develops, 
in animals of all tribes, an exceedingly important and 
interesting animal form, which, in my Monograph of the 
Calcareous Sponges, I have named Gastrula (that is, larva 
with a stomach or intestine). (Frontispiece, Fig. 5, 6). This 
Gastrula externally resembles the Planula, but differs es- 
sentially from it in the fact that it encloses a cavity which 
opens to the outside by a mouth. The cavity is the " pi^i- 
mary intestine," or "primary stomach," the progaster, the 
first beginning of the alimentary canal ; its opening is the 
" prirnaTy mouth" (prostoma). The wall of the progaster 
consists of two layers of cells ; an outer layer of smaller 
ciliated ceUs (outer skin, or ectoderm), and of an inner 
layer of larger non-ciliated cells (inner skin, or entoderm). 
This exceedingly important larval form, the " Gastrula," 
makes its appearance in the ontogenesis of all tribes of 


Definition of fhe forms 
of the five first stages 
of the development of 
the animal body. 

First Stage of Develop, 

A simple cytod (a 
plastid -without a ker- 

Second Stage of Develop- 
A simple cell (a 
plastid containing a 

Third Stage of Develop- 
A community (an 
aggregation of identi- 
cal simple cells). 

Fourth Stage of Develop, 

A solid or bladder- 
shaped, globular, or oval 
body, co7n2'yosed of two 
hinds of different cells: 
externally ciliated, in. 
ternally non - ciliated 

Fifth Stage of Develop, 
A globular or oval 
body with simple inies. 
tinal cavity and mouth, 
opening. Body wall com. 
posed of two layers; an 
externally ciliated ecto- 
derm (dermal layer), an 
internally non - ciliated 
entoderm (gas tral layer), 


The five first stages 
of the individual de. 


Animal egg without a 
kernel (when the egg- 
kernel has disappeared, 
after being fructified). 


Animal egg with ker. 
nel (a simple egg-cell) . 


(Mulberry form.) 
Globular heap of ho- 
mogeneous *' cleavage 


(Ciliated larva.) 
Many - celled larva 
without mouth, com- 
posed of different cells. 

(Larva with tnouth.) 
Many-celled "n^ith in- 
testines and month; in- 
testinal wall with two 

The five first stages 
of the phyletic or his- 
torical development. 

Most ancient animal 
Monera, originating by 
spontaneous generation. 



Animal Amoebis, 

An aggregation of 

Mnny-celled prim- 
aeval animal without 
mouth, composed of 
two kinds of diiferent 


Many -celled prim- 
aeval animal with intes- 
tine and mouth ; intes- 
tinal wall with two 
layers. (PHmary form 
of zoophytes and 



animals — In Sponges, Medusse, Corals, Worms, Sea-squirts 
Radiated animals. Molluscs, and even in the lowest Ver- 
tebrata (Amphioxus : compare p. 200, Plate XII., Fig. B 4! ; 
see also in the same place the Ascidian, Fig. A 4). 

From the ontogenetic occurrence of the Gastrula in the 
most different animal classes, from Zoophytes up to Ver- 
tebrata, we may, according to the biogenetic principle, safely 
draw the conclusion that during the Laurentian period there 
existed a common primary form of the six higher anima, 
tribes, which in all essential points was formed like the 
Gastrula, and which we shall call the Gastrsea. This Gastrsea 
possessed a perfectly simple globular or oval body, which 
enclosed a simple cavity of like form, namely, the progaster ; 
at one of the poles of the longitudinal axis the primary 
intestine opened by a mouth which served for the reception 
of nutrition The body wall (which was also the intestinal 
wall) consisted of two layers of cells, the unfringed entoderm, 
or intestinal layer, and the fringed ectoderm, or skin-layer ; 
by the motion of the cilia or fringes of the latter the 
Gastrasa swam about freely in the Laurentian ocean. Even 
in those higher animals, in the ontogenesis of which the 
original Gastrula form has disappeared, according to the laws 
of abbreviated inheritance (vol. i. p. 212), the composition 
of the Gastrsea body has been transmitted to the phase 
of development which directly arises out of the Morula. 
This phase is an oval or round disc consisting of two cell- 
layers or membranea : the outer cell-layer, the animal or 
dermal layer (ectoblast), corresponds to the ectoderm of 
the Gastrffia ; out of it develops the external, loose skin 
(epidermis), with its glands and appendages, as well as 
the central nervous system. The inner cell-layer, the 


vegetative or intestinal layer (hypoblast), is originally the 
entoderm of the Gastrsea; out of it develops the inner 
membrane (epithelium) of the intestinal canal and its glands. 
(Compare my Monograph of the Calcareous Sponges, voL i. 
p. 466, etc.) 

By ontogeny -we have already gained five primordial 
stages of development of the animal kingdom : (1) the 
Moneron ; (2) the Amceba ; (3) the Synamoeba ; (4) the 
Plansea ; and (5) the Gastrsea. The former existence of 
those five oldest primary forms, which succeeded one another, 
and which must have lived in the Laurentian period, follows 
as a consequence of the biogenetic principle ; that is to s&j, 
from the parallelism and the mechanico-causal connection of 
ontogenesis and phylogenesis. (Compare vol. i. p. 309.) In our 
genealogical system of the animal kingdom we may class 
all these animal forms, long since extinct, and, which on 
account of the soft nature of their bodies could leave no 
fossd remains, among the tribe of Primaeval animals 
(Protozoa), which also comprises the stiU living Infusoria 
and Gregarinse. 

The phyletic development of the six higher animal tribes, 
which are all derived from the Gastrsea, deviated at this 
point in two directions. In other words, the Gastrceads 
(as we may call the group of forms characterized by the 
Gastrsea-tj^e of structure), divided into two divergent 
lines or branches; the one branch of Gastrseads gave up 
free locomotion, adhered to the bottom of the sea, and thus, 
by adopting an adhesive mode of life, gave rise to the Pro- 
tascus, the common primary form of the Animal-planis 
(Zoophyta). The other branch of the Gastracads retained 
free locomotion, did not become adlierent and later on 


developed into the Prothelmis, the common primary form 
of Worms (Vermes). (Compare p. 133.) 

This latter tribe (as limited by modern zoology) is of the 
greatest interest in the study of genealogy. For among 
Worms, as we shall see later, there are, besides very nume- 
rous peculiar families, and besides many independent 
classes, also very remarkable forms, which may be con- 
sidered as forms of direct transition to the four higher 
animal tribes. Both comparative anatomy and the on- 
togeny of these worms enable us to recognize in them 
the nearest blood relations of those extinct animal forms 
which were the original primary forms of the four higher 
animal tribes. Hence these latter, the Molluscs, Star-fishes, 
Articulated animals, and Vertebrate animals, do not stand 
in any close blood relationship to one another, but have 
originated independently in four different places out of the 
tribe of Worms. 

In this way comparative anatomy and phylogeny lead us 
to the raonophyletio 'pedigree of the animal kingdom, the 
outlines of which are given on p. 133. According to it the 
seven phyla, or tribes, of the animal kingdom are of different 
value in regard to genealogy. The original primary group 
of the whole animal kingdom is formed by the Primsevai 
animals (Protozoa), including the Infusoria and Gastrseads. 
Out of these latter arose the two tribes of Animal-plants 
(Zoophyta) and Worms as diverging branches. Out of four 
different groups of the Worm tribe, the four higher tribes 
of the animal kingdom were developed — the Star-fishes 
(Echinoderma) and Insects (Arthropoda) on the one hand, 
and the Molluscs (Mollusca) and Vertebrated animals 
(V'ertebrafa) on the other. 


Having thus sketched out the monophyletic pedigree of 
the animal kingdom in its most important features, we must 
now turn to a closer examination of the historical course of 
development which the seven tribes of the animal kingdom, 
and the classes distinguished in them, have passed through 
(p. 132). There is a much larger number of classes in 
the animal than in the vegetable kingdom, owing to the 
simple reason that the animal body, in consequence of its 
more varied and perfect vital activity, could differentiate 
and develope in very many more different directions than 
could the vegetable body. Thus, while we were able to 
divide the whole vegetable kingdom into six main classes 
and nineteen classes, we have to distinguish, at least, sixteen 
main classes and thirty-eight classes in the animal kingdom. 
These are distributed among the seven different tribe.s of the 
animal kingdom in the way shown in the Systematic Survey 
on pages 132 and 133. 

The group of PrimcBval animals (Protozoa) within the 
compass which we here assign to this tribe, comprises the 
most ancient and the simplest primary forms of the animal 
kingdom; for example, the five oldest phyletic stages of 
development previously mentioned, and besides these the 
Infusoria and Gregarina;, as well as aU those imperfect 
animal forms, for which, on account of their simple and in- 
different organization, no place can be found in any of the 
other six animal tribes. Most zoologists, in addition to these, 
include among the Protozoa a larger or smaller portion of 
those lowest organisms, which we mentioned in our neutral 
kingdom of Protista (in Chapter XVI.). But these Protista, 
especially the large division of the Rhizopoda, which are so 
rich in forms, cannot be considered as real animals for 




Of iliG 16 Main Classes and 38 Classes of tJie Animal Kingdom. 

Ti-ibes or Phyla 

of the. 
Animal Kw{/dom. 

Main Classes, 
Branches or Clades 

of the 
Animal Kingdom. 

oj' the 
Animal Kingdom. 

Si/stematic Naine 
of the 

A. 1 


I. Esrgr-animals 

1. Archaic animals 

2. Gregarines 

3. Infusoria 

1. Archezoa 

2. Gregarinffi 

3. Infusoria 


II. Mulberry animaJs r 4. Plaiiseads 
Blastularia \ 5. Gastraads 

4. Planaiadas 

5. Gastrseadas 

B. , 




III. Spongea / 6. Sponges 

SnonauE *■ 
,„„.», f 7. Corals 
IV. SGa-nettles . e. Hood-jelliea 
Acalephce | 9. Comb-jeUies 

6 Porifcra 

7. Coralla 

8. Ilydromedusas 

9. Ctenophora 

" 1 

JUHnrms ^ 
Vermes j 

V. Bloodless worms {10. Planary worms 

,11. Roundworms 
VI. Blood-bearing 12. Moss-polypa 
worms 13. Sac-worms .^ 
Cctlumati J 11. Proboecideana 
15. Star-worms 
le. WTieel auimal- 
V I cules 

17. Eing-wormB 

10. Platyhelmiuthes 

11. Nemathelminthcs 
13. Bryozna 

13. Tunicata 

14. Rhynchoco3la 

15. Gephyrea 

16. Eotatoria 

17. Auuelida 


fHolhiscs . 

VII. Headless shell- j jg j,„mp.sbell3 

fish i i9_ Mussels 

VIII. Heart-bearing ( 20. .^Inailg 

l^ EacepMla | 21. CuUlcs 

18. Spirobranchia 

19. Lamellibranchia 

21. Cnchlidos 
21. Ceplialopoda 


Slar=flsljc3 - 

IX. T!iii»ed-arms 

X. Armless 

22. Sea-stars 
[ 23. Lily -stars 

( 24. Sea-urchins 
1 2.1. Sea-cucumbera 

22. Asterida 
2.3. Crinoida 

24. Echinida 

25. Holothuriaj 





XI. Gill-breathers 

XII. Tube-breathers 

{ 2G. Crab-fish 

27. Spiders 
2S. Centipcdca 
2y. llies 

20. Crustacea 

27. Arachnida 

28. Jlyriopoda 

29. Insocta ' 

/ XIII. Skull-less 

{ 30. Lanceleta 

"0. Leptocardia 


VerteTirata i^ 

XIV. Sing-le-noa- 


XV. Amnion -less 

\ 31. Lampreys 

/ 32. Fishes 
33. JIud-fish 

.34, Sea-dray;on3 

. 35. Amphibians 

31. Cyclostoma 

32. Pisces 

33. Dipneusta 

34. Halisauiia 

35. Amphibia 

XVI. Amnion- 
1 bearing; 
\ Aiiiidota 

Sf). r.cptilos 
• 37. Birds 
, .18. Mammals. 

3fi. Reptilia 

.37. Aves 

38. ]\Iammalia 





{Articulated Animals) 


{Yertehrated animals) 

Lipobrachia Crustacea 

I Annelida 












(Worvis with a iody-cavity) 


Zoophyta ^" >■ ^ 

(Animal Plants) Acoelomi 

Spongia3 Acalephse (Worms without body-cavity) 




(Primarval anivials) 










reasons previously given. Hence, if we hero leave them out 
of the question, vre niay accept two main classes or provinces 
of real Protozoa, namely, Egg animals (Ovularia) and Germ 
animxils (Blastularia). To the fonner belong the three 
classes of Archezoa, Gregarinas, and Infusoria, to the latter 
the two classes of PlanfEads and Gastrseads. 

The first province of the Protozoa consists of the Egg 
animals (Ovularia) ; we include among them all single- 
celled anivials, aU animals whose body, in the fully 
developed state, possesses the form-value of a simple 
plastid (of a cytod or a cell), also those simple animal forms 
whose body consists of an aggTegation of several cells per- 
fectly similar one to another. 

The Archaic animals (Archezoa) form the first class 
in the series of Egg animals. It contains only the most 
simple and most ancient piimary forms of the animal 
kingdom, whose former existence we have proved by means 
of the fundamental law of biogenesis; they are, (1) Animal 
Monera ; (2) Animal Amoebse ; (3) Animal Synamoebje. We 
may, if we choose, include among them a portion of the 
stiU living Monera and Amoebse, but another portion (ac- 
cording to the discussion in Chapter XVI.) must on account 
of their neutral nature be considered as Protista, and a third 
portion, on account of their vegetable nature, must be con- 
sidered as plants. 

A second class of the egg animals consists of the Groga- 
rines (Gregarinas), which live as parasites in the intestines 
and body-cavities of many animals. Some of these Grega- 
rines are perfectly simple cells like the Amoeba} ; some form 
chains of two or three identical cells, one lying behind the 
other. They difi'er from the naked Amoebae by possessing 


a thick, simple membrane, which surrounds their ceU-hody ; 
they can be considered as animal Amoebae which have 
adopted a parasitical mode of life, and in consequence have 
surrounded themselves with a secreted covering. 

As a third class of egg animals, we adopt the real 
Infusoria (Infusoria), embracing those forms to which 
modern zoology almost universally limits this class of 
animals. The principal portion of them consists of the 
small ciliated Infusoria (Ciliata), which inhabit aU the fresh 
and salt waters of the earth in great numbers, and which 
swim about by means of a delicate garb of vibratile fringes. 
A second and smaller division consists of the adherent 
sucJcing Infusoria (Acinetse), which take their food by means 
of fine sucking-tubes. Although during the last thirty 
years numerous and very careful investigations have been 
made on these small animalcules, — which are mostly in- 
visible to the naked eye, — still we are even now net very 
sure about their development and form- value. We do not 
even yet know whether the Infusoria are single or many- 
celled ; but as no investigator has as yet proved their body to 
be a combination of cells, we are, in the mean time, justified 
in considering them as single-celled, like the Gregarines and 
the Amoebae. 

The second main class of primaeval animals consists of the 
Germ animals (Blastularia). This name we give to those 
extinct Protozoa which correspond to the two ontogenetic 
embryonic forms of the six higher animal tribes, namely, the 
Planula and the Gastrula. The body of these Blastularia, in a 
perfectly developed state, was composed of many cells, and 
these cells moreover differentiated — in two ways at least — 
into an external (animal or dermal) and an internal 


(vegetative or gastral) mass. Whether there still exist 
representatives of this group is uncertain. Their former 
existence is undoubtedly proved by the two exceedingly 
important ontogenetic animal forms which we have already 
described as Planula and Gastrula, and which stUl occur as a 
transient stage of development in the ontogeny of the most 
different tribes of animals. Corresponding to these, we may, 
according to the biogenetic principle, assume the former 
existence of two distinct classes of Blastularia, namely, the 
Planceada and Gastrceada. The type of the Planceada is 
the Flanma — long since extinct — ^but whose historical por- 
trait is still presented to us at the present day in the widely 
distributed ciliated larva (Planula). (Frontispiece, Fig. 4.) 
The type of the Gastrasada is the Gastrma, of Vi^hose 
original nature the mouth-and-stomach larva (Gastrula), 
which recurs in the most different animal tribes, still gives 
a faithful representation. (Frontispiece Fig. 5, 6.) Out of the 
Gastraea, as we have previously mentioned, there were at 
one time developed two different primary forms, the Pro- 
taacus and Prothelmis ; the former must be looked upon as 
the primary form of the Zoophytes, the latter as the primary 
form of Worms. (Compare the enunciation of this hypothesis 
in my Monograph of the Calcareous Sponges, vol. i. p. 464.) 

The Animal-plants (Zoophyta, or Coelenterata) which con- 
stitute the second tribe of the animal kingdom, rise con- 
siderably above the primitive animals in the characters of 
their whole organisation, while they remaiQ far below most 
of the higher animals. For in the latter (with the excep- 
tion only of the lowest forms) the four distinct functions of 
nutrition — namely, digestion, circulation of the blood, 
respiration, and excretion — are universally accomplished by 


four perfectly different systems of organs ; by the intestines, 
the vascular system, the organs of respiration, and the 
urinary apparatus. In Zoophytes, however, these functions 
and their organs are not yet separate, and are all performed 
by a single system of alimentary canals, by the so-called 
gastrd-vascular system, or the coelenteric apparatus of the 
intestinal cavity. The mouth, which is also the anus, leads 
into a stomach, into which the other cavities of the body also 
open. In Zoophytes the body-cavity, or "coeloma," possessed 
by the four higher tribes of animals is still completely 
wanting, likewise the vascular system and blood, as also the 
organs of respiration, eta 

AU Zoophytes live in water; most of them in the sea, only 
a very few in fresh water, such as fresh-water sponges 
(Spongilla) and some primaeval polyps (Hydra, Cordylo- 
phora). A specimen of the pretty flower-like forms which 
are met with in great variety among Zoophytes is given on 
Plate VII. (Compare its explanation in the Appendix.) 

The tribe of animal-plants, or Zoophytes, is divided into 
two distinct provinces, the Sponges, or SpongicB, and the Sea- 
nettles, or AcalephcB (p. 144). The latter are much richer 
in forms and more highly organized than the foi-mer. In all 
Sponges the entire body, as well as the iadividual organs, 
are differentiated and perfected to a much less extent than 
in Sea-nettles. AH Sponges lack the characteristic nettle- 
organs which all Sea-nettles possess. 

The common primary form of all Zoophytes must be 

looked for in the Protascus, an animal form long since 

extiact, but whose existence is proved according to the 

biogenetic principle by the Ascula. This Ascula is an 

ontogenetical development form which, in Sponges as well 



as in Sea-nettles, proceeds from the Gastrula. (Compare the 
Ascula of the calcareous sponge on the Frontispiece, Fig 7, 8.) 
For after the Gastrula of zoophytes has for a time swum 
about ia the -water it sinks to the bottom, and there adheres 
by that pole of its axis which is opposite to the opening of 
the mouth. The external cells of the ectoderm draw in 
their vibrating, ciliary hairs, whereas, on the contrary, the 
inner cells of the entoderm begin to form them. Thus the 
Ascula, as we call this changed form of larva, is a simple 
sack, its cavity (the cavity of the stomach or intestiae) 
opening by a mouth externally, at the upper pole of the 
longitudinal axis (opposite the basal point of fixture). The 
entire body is here in a certain sense a mere stomach or 
intestinal canal, as in the case of the Gastrula. The wall of 
the sack, which is both body wall and intestinal wall, con- 
sists of two layers or coats of cells, a fringed entoderm,, 
or gastral layer (corresponding with the inner or vegeta- 
tive germ-layer of the higher animals), and an unfringed 
exoderm or dermal layer (corresponding with the external 
or animal germ-layer of the higher animals). The origiaal 
Protascus, a true likeness of which is still furnished by 
the Ascula, probably formed egg-cells and sperm-ceUs out 
of its gastral layer. 

The Protascads — as we will eaU the most ancient group 
of vegetable animals, represented by the Protascus-type — 
divided into two lines or branches, the Spongice and the 
Sea-nettles, or Aealephse. I have shown in my Monograph 
of the Calcareous Sponges (vol. i. p. 485) how closely these 
two main classes of Zoophytes are related, and how they 
must both be derived, as two diverging forms, from the 
Protascus-form. The primary form of Sjpongise, which I 


have tliero called Arcliispongia, arose out of the Protascus 
by the formation of pores through its body- wall; the 
primary form of Sea-nettles, which I there called Archydra, 
developed out of the Protascus by the formation of nettle- 
organs, as also by the formation of feelers or tentacles. 

The main-class or branch of the Sponges, Spongice, or 
Porifera, lives in the sea, with the single exception of the 
green fresh-water Sponge (Spongilla). These animals were 
long considered as plants, later as Protista; in most 
Manuals they are still classed among the primceval animals, 
or Protozoa. But since I have demonstrated their develop- 
ment out of the Gastrula, and the construction of their 
bodies of two cellular germ-layers (as in all higher animals), 
their close relationship to Sea-nettles, and especially to the 
Hydrapolyps, seems finally to be established. The Olynthus 
especially, which I consider as the common primary form of 
calcareous sponges, has thrown a complete and unmistak- 
able light upon this point. 

The numerous forms comprised in the class of Spongise 
have as yet been but little examined ; they may be divided 
into three legions and eight orders. The first legion consists 
of the soft, gelatinous Mucous Sponges (MyxospongiaB), 
which are characterized by the absence of any hard 
skeleton. Among them are, on the one hand, the long-since- 
extinct primary forms of the whole class, the type of which 
I consider to be the Archispongia ; on the other hand there 
are the still hving, gelatinous sponges, of which the Halisarca 
is best known. We can obtain a notion of the Archispongia, 
the most ancient primaeval sponge, if wo imagine the 
Olynthus (see Frontispiece), to be deprived of its radiating 
calcareous spiculse. 


The second legion of Spongi^ contains the Fibrous 
Sponges (Fibrospongise), the soft body of which is supported 
by a firm, fibrous skeleton. This fibrous skeleton often 
consists merely of so-called " horny fibres," formed of a very 
elastic, not readily destructible, organic substance. This is 
the case for instance in our common bathing Sponge 
(Euspongia officinalis), the purified skeleton of which we 
use every morning when washing. Blended with the 
horny, fibrous skeleton of many of these Sponges, there 
are numerous fl[inty spicula ; this is the case for example 
with the fresh-water Sponge (Spongilla). In others the 
whole skeleton consists of only calcareous or silicious spicula 
which are frequently interwoven into an extremely beautiful 
lattice-work, as in the celebrated Venus' Flower Basket 
(Euplectella). Thi'ee orders of fibrous sponges may be 
distinguished according to the different fox'mation of the 
spicula, namely, Chalynthina, Geodina, and Hexactinella. 
The natural history of the fibrous sponges is of especial 
interest to the Theory of Descent, as was first shown by Oscar 
Schmidt, the greatest authority on this group of animals. 
In no other group, perhaps, can the unlimited pliability of 
the specific form, and its relation to Adaptation and Inherit- 
ance, be so clearly followed step by step; perhaps in no 
other group is the species so difficult to limit and define. 

This proposition, which applies to the great legion of the 
Fibrous Sponges, applies in a still higher degree to the 
smaller but exceedingly interesting legion of the calcareous 
sponges (Calcispongias), on which in 1872, after five years' 
careful examination, I published a comprehensive Mono- 
graph. The sixty plates of figures accompanying this Mono- 
graph explain the extreme pliability of these small sponges 



" good species " of which, in fact, cannot be spoken of in the 
usual systematic sense. We find among them only varying 
series of forms, which do not even completely transmit their 
specific form to their nearest descendants, but by adaptation 
to subordinate, external conditions of existence, perpetually 
change. It frequently occurs here, that there arise out of 
one and the same stock different form-species, which accord- 
ing to the usual system would belong to several quite distinct 
genera ; this is the case, for instance, with the remarkable 
Ascometra (Frontispiece, Fig. 10.) The entire external bodily 
form is much more pliable and protean in Calcareous Sponges 
than in the silicious sponges, which are characterized by 
possessing silicious spicula, forming a beautiful skeleton. 
Through the study of the comparative anatomy and ontogeny 
of calcareous sponges, we can recognise, with the greatest 
certainty, the common primary form of the whole group, 
namely, the sack-shaped Olynthus, whose development is 
represented in the Frontispiece (compare its explanation in 
the Appendix). Out of the Olynthus (Fig. 9 on the Frontis- 
piece), the order of the Ascones was the first to develop, out 
of which, at a later period, the two other orders of Cal- 
careous Sponges, the Leucones and Sycones, arose as diverg- 
ing- branches. Within these orders, the descent of the 
individual forms can again be followed step by step. Thus 
the Calcareous Sponges in every respect confirm the pro- 
position which I have elsewhere maintained: that "the 
natural history of sponges forms a connected and striking 
argument in favour of Darwin." 

The second main class or branch in the tribe of Zoophytes 
is formed by the Sea-nettles (Acalephee, or Cnidse). This 
interesting group of animals, so rich in forms, is composed 


of three different classes, namely, the Hood-jeUies (Hydro- 
medusae), the Comb-jeUies (CtenojDhora), and the Corals 
(Coralla). The hypothetical, extinct Archydra must be 
looked upon as the common primary form of the whole 
group; it has left two near relations in the still living 
fresh-water polyps (Hydra and Cordylophora). The 
Archydra was very closely related to the simplest forms 
of Spongiae (Archispongia and Olynthus), and probably 
differed from them only by possessing nettle organs, and 
by the absence of cutaneous pores. Out of the Archydi-a 
there first developed the diflerent Hydroid polyps, some 
of which became the primary forms of Corals, others the 
primary forms of Hydromedusse. The Ctenophora de- 
veloped later out of a branch of the latter. 

The Sea-nettles differ from the Spongise (with which 
they agree in the characteristic formation of the system of 
the alimentary canal) priacipaUy by the constant posses- 
sion of nettle organs. These are small bladders filled with 
poison, large numbers — -generally millions — of which arc 
dispersed over the skia of the sea nettles, and which burst 
and empty their contents when touched. Small animals 
are killed by this ; ia larger animals this nettle poison 
causes a slight inflammation of the skin, just as does the 
poison of our common nettles. Any one who has often 
bathed in the s^a, will probably have at times come in con- 
tact with large Hood-jellies (Jell3'--fish), and become ac- 
quainted with the unpleasant burning feeling which their 
nettle organs can produce. The poison in the splendid blue 
Jelly-fish, Physalia, or Portuguese Man-of-war, acts so 
powerfully that it may lead to the death of a human being. 

The class of Corals (Coralla) lives exclusively in the sea. 


and is more especially represented in the warm seas by an 
abundance of beautiful and highly-coloured forms like 
flowers. Hence they are also called Flower-aniTnals 
(Anthozoa). Most of them are attached to the bottom 
of the sea, and contain an internal calcareous skeleton. 
Many of them by continued growth produce such im- 
mense stocks that their calcareous skeletons have formed 
the foundation of whole islands, as is the case with the 
celebrated coral reefs and atolls of the South Seas, the re- 
markable forms of which were first explained by Darwin.^* 
In corals the counterparts, or antimera — that is, the cor- 
responding divisions of the body which radiate from and 
surround the central main axis of the body — exist some- 
times to the number of four, sometimes to the number of 
six or eight. According to this we distinguish three legions, 
the Fourfold (Tetracoralla), Sixfold (Hexacoralla), and Eight- 
fold corals (Octocoralla). The fourfold corals form the 
common primary group of the class, out of which the six- 
fold and eightfold have developed as two diverging branches. 
The second class of Sea-nettles is formed by the Hood- 
jellies (Medusae) or Polyp- jellies (Hydromedusse). While 
most corals form stocks like plants, and are attached to 
the bottom of the sea, the Hood-jeUies generally swim about 
freely in the form of gelatinous bells. There are, however 
numbers of them, especially the lower forms, which adhere 
to the bottom of the sea, and resemble pretty little trees. 
The lowest and simplest members of this class are the 
little fresh-water polyps (Hydra and Cordylophora). We 
may look upon them as but little changed descendants of 
those FrimcBval jiolyps (Archydrge), from which, during the 
primordial period, the whole division of the Sea-nettles 



Of the 4 Classes and 30 Orders of ilie Animal Plants, or Zoophytes. 

classes of the 

Lfmons of the 

Orders nf the 

A Genus Name 
as example. 















I. Mysosponrrias 
Mucous SjJonges 

II. Fibrospongia3 
Filrous Sponges 

III. CaloispoDgiao 
Calcareous Sponges 

IV. Tetracoralla 
Fourfold Corals 

V. Hexacoralla 
Sixfold Corals 

Yl. Octocoralla 
Eightfold Corals 

^ 1. Arcliisponf;ina 
^ 2. Halisai'ciua 

3. Chalynthina 

4. Geodina 

5. Hexacfcinella 

6. Asconcs 

7. Leucones 

8. Syooncs 

5 9- Kngosa 

( 10. Paranemcta 

( 11. Cauliculata 
\ 12. Madreporaria 
' 13. Halirhoda 

14. Alcjonida 

15. Gorgonida 

16. Peunatulida 

VII. Arcliydraj 
PriTuceval Polyps 

VIII. Leptomedusoe 
Soft Jelly-fish 

IX. TracliymednsaD 
Hard Jelly-fish 

X. CalycoEoa 
Stalked Jellies 

XI. Discomedusas 

17. Hydraria 

' 18. Vesiculata 

19. OoeUata 

20. Siplionophora 

21. Marsiporchida 

22. Phyllorcbida 

23. Elasmurchida 

■ 24. Fodaotinaria 



XIT. Eurystoma 

XIII. Stenostoma 
Narrow-mouth ed 

27. Beroida 

2S. Saccata 

29. Lobata 

30. Treniata 






















Tocuiafca Lobata 













FibrospoDgiaa Calcispongis 
Chalynthina Leucones Sycones 


Geodina Dyssyons Sycarns 






Olynthus I 







originated. Scarcely distlnguisliable from the Hydra are the 
adherent Hydroid polyps (Campanularia, Tubularia), which 
produce freely swimming medusas by budding, and out 
of the eggs of these there again arise adherent polyps. 
These freely swimming Hood-jellies are mostly of the form 
of a mushroom, or of an umbrella, from the rim of which 
many long and delicate tentacles hang. They are among the 
most beautiful and most interesting inhabitants of the sea. 
The remarkable history of their lives, and especially the 
complicated alternation of generation of polyps and me- 
dusiB, are among the strongest proofs of the truth of the 
theory of descent. For just as Medusae still daily arise out 
of the Hydroids, did the freely swimming medusa-form 
originally proceed, phylogenetically, out of the adherent 
polyp-form. Equally important for the theory of descent is 
the remarkable division of labour of the individuals, which 
among some of them is developed to an astonishingly high 
degree, more especially in the splendid Biiihonojjhora.^ 
(Plate VII. Fig. 13). 

The third class of Sea-nettles — the peculiar division of 
Comb-jellies (Ctenophora), probably developed out of a 
branch of the Hood-jellies. The Ctenophora, which are also 
called Pdbbed-jellies, possess a body of the form of a cu- 
cumber, which, like the body of most Hood-jellies, is as clear 
and transparent as crystal or cut glass. Comb or Ribbed- 
jellies are characterized by their peculiar organs of motion, 
namely, by eight rows of paddling, ciliated leaflets, which run 
in the form of eight ribs from one end of the longitudinal axis 
(from the mouth) to the opposite end. Those with narrow 
mouths (Stenostoma) probably developed later out of those 
with wide mouths (Euiystoma). (Compare Plate VII. Fig. 16.) 


The third tribe of the animal kingdom, the phylum of 
WoTTns or worm-like animals (Vermes, or Hehninthes), con- 
tains a number of diverging branches. Some of these 
numerous branches have developed into well-marked and 
perfectly independent classes of Worms, but others changed 
long since into the original, radical forms of the four higher 
tribes of animals. Each of these four higher tribes (and 
likewise the tribe of Zoophytes) we may picture to ourselves 
in the form of a lofty tree, whose branches represent the 
different classes, orders, families, etc. The phylum of Worms, 
on the other hand, we have to conceive as a low bush or 
shrub, out of whose root a mass of independent branches 
shoot up in different directions. From this densely 
branched shrub, most of the branches of which are dead, 
there rise four high stems with many branches. These 
are the four lofty trees just mentioned as representing the 
higher phyla — the Echinoderma, Articulata, MoUusca, and 
Vertebrata. These four stems are directly connected with 
one another at the root only, to wit, by the common primary 
group of the Worm tribe. 

The extraordinary difficulties which the systematic ar- 
rangement of Worms presents, for tliis reason merely, are 
still more increased by the fact that we do not possess any 
fossil remains of them. Most of the Worms had and still 
have such soft bodies that they could not leave any 
characteristic traces in the neptunic strata of the earth. 
Hence in this case again we are entirely confined to the 
records of creation furnished by ontogeny and comparative 
anatomy. In making then the exceedingly difficult at- 
tempt to throw a few hypothetical rays of light upon the 
obscurity of the pedigree of Worms, I must therefore 


expressly remark that this sketch, like all similar attempts 
possesses only a provisional value. 

The numerous classes distinguished in the tribe of Worms, 
and which almost every zoologist groups and defines accord- 
ing to his own personal views, are, in the first place, divided 
into two essentially different groups or branches, which in 
my Monograph of the Calcareous Sponges I have termed 
Acoelomi and CoslomatL For all the lower Worms which 
are comprised in the class of Flat-worms (Platyhelminthes) , 
(the Gliding-worms, Sucker- worms. Tape-worms), differ very 
strikingly from other Worms, in the fact that they possess 
neither blood nor body-cavity (no coelome) ; they are, there- 
fore, called Acoelomi. The true cavity, or coelome, is com- 
pletely absent in them as in all the Zoophytes ; in this im- 
portant respect the two groups are directly allied. But all 
other Worms (like the four liigher tribes of animals) possess 
a genuine body-cavity and a vascular system connected with 
it, which is filled with blood ; hence we class them together 
as Ccalomati. 

The main division of Bloodless ^Yornls (Acoelomi) con- 
tains, according to our phylogenetic views, besides the still 
living Flat-worms, the imknown and extinct primary 
forms of the whole tribe of Worms, which we shall call the 
Primajval Worms (Archehninthes). The type of these 
Primceval Worms, the ancient Prothelmis, may be directly 
derived from the Gastrsea (p. 133). Even at present the 
Gastrula-form — the faithful historical portrait of the 
Gastraaa — recurs in the ontogenesis of the most difierent 
kinds of worms as a transient larva-form. The ciliated 
Gliding-wonns (Turbellaria), the primary group of the 
present Planary or Flat-worms (Platyhelminthes), are the 


nearest akin to the Primeval Worms, The parasitical 
Sucker-worms (Trematoda) arose out of the Gliding-worms, 
which live freely in water, by adaptation to a parasitical 
mode of life ; and out of them later on — ^by an increasing 
parasitism — arose the Tape-worms (Cestoda). 

Out of a branch of the Acoelomi arose the second main 
division of the Worm tribe, the Worms with blood and 
body-cavity (Coelomati) : of these there are seven different 

The Pedigree on p. 151 shows how the obscure phylogeny 
of the seven classes of Coelomati may be supposed to stand. 
We shall, however, mention these classes here quite briefly, 
as their relationships and derivation are, at present, still 
very complicated and obscure. More numerous and more 
accurate investigations of the ontogeny of the different 
Coelomati will at some future time throw light upon their 

The Round Worms (Nemathelminthes) which we mention 
as the first class of the Coelomati, and which are character- 
ized by their cylindrical form, consist principally of para- 
sitical Worms which live in the interior of other animals. 
Of human parasites, the celebrated Trichinse, the Maw- 
worms, Whip-worms, etc., for example, belong to them. The 
Star-worms (Gephyrea) which live exclusively in the sea are 
allied to round worms, and the comprehensive class of Ring- 
worms (Annelida) are allied to the former. To the Ring- 
worms, whose long body is composed of a number of seg- 
ments, all alike in structure, belong the Leeches (Hirudinea), 
Earth-worms (Lumbricina), and all the marine bristle-footed 
Worms (Ch^topoda). Nearly akin to them are the Snout- 
worms (Rhynchocoela), 'and the small microscopic Wheel- 



Of the 8 Classes and 22 Orders of the Worm Tribe. 

(Comparo Gen. Morpli. II. Plate V. pp. 7S-77.) 


of Ihi-. 

Worm Ti-ilK. 

Orders of the 
Worm IrU/i. 


NaiRR of Uif. 

Orders qf Worms. 

Name of a Oenus 
as example. 

1. Flat 

■ 1. PrimsBval worm3 

1. Arehclminthes 



2. Gliding-worms 

2. Turbellaria 


Platyhel- '^ 

3. Sucker-worms 
^ 4. Tape-worms 

3. Trematoda 

4. Ceatoda 


2. Round, 

5. Arrow-worms 

6. Cliaitognatha 



6. Thread-worms 

6. Nematoda 



7. Hook-headed 

7. Aeauthoccphala 


3. Woas 1 
Brjozoa J 

8. Horse-shoo-lipped 

9. Circle-lipped 

8. Lophopoda 

9. Stclmopoda 


4. Sea-sacs . 

' 10. Sea-squirt.'? 

10. Ascidia 


Tunica ta 

_ 11. Sea-barrels 

11. Thaliacea 


5. Prohos- \ 

12. Tongue.worms 

12. Enteropncusta 



13. Cord-worms 

13. Nemertina 


C. Star- 
Worms . 

14. Star-worms with. 

out bristles 

15. Slav -worms witli 


14. SipuncuHda 

15. Eohiurida 


7. Wheel j 

Anitnaicule [ 

Rotif<3ra ) 

IG, "Wlieel-woriiis 

16, Rotatoria 


^M\llli^\J^UI f 

' 17. Bear-worms 

17. Arctlsca 


18. Worms with claws 

18. Onychophora 


8. B.inij 

19. Leeches 

19. Hirudinea 



20. Land-worms 

21. Mailed worms 

20. Drilomorpha 

21. Phracthelminthes 


22. Bristle-footed 

22. Ohcotopoda 



















Tlialicea Nemertina 



CcElomati (^vorms with body-cavity) 


Pla uy helminthes 

Acoelomi (worms uiithout body-cavity) 




worms (Rotifera). The unknown, extinct, primary forms 
of the tribe of Sea-stars (Eehinoderma), and of the tribe 
of the articulated animals (Arthropoda), were nearest akin 
to the Ring-worms. On the other hand, we must probably 
look for the primary forms of the great tribe of Molluscs in 
extinct Worms, which were ver'y closely related to the 
Moss-polyps (Bryozoa) of the present day; and for the 
primary forms of the Vertebrata in the unknown Coelomati, 
whose nearest kin of the present day are the Sea-sacs, 
especially the Ascidia. 

The class of Sea-sacs (Tunicata) Is one of the most 
remarkable among Worms. They all live in the ocean, 
where some of the Ascidire adhere to tlie bottom, while 
others (the sea -barrels, or Thaliacea) swim about freely. In 
all of them the non-jointed body has the form of a simple 
barrel-shaped sack, which is surrounded by a thick cartila- 
ginous mantle. This mantle consists of the same non- 
nitrogenous combination of carbon, which, under the name 
of cellulose, plays an important part in the Vegetable King- 
dom, and forms the largest poiiion of vegetable cellular 
membranes, and consequently also the greater part of wood. 
The barrel-shaped body generally possesses no external ap- 
pendages. No one would recognise in them a trace of rela- 
tionship to the highly differentiated vertebrate animals. 
And yet this can no longer be doubted, since Kowalewsky's 
investigations, which in the year 1SG7 suddenly tlarew an 
exceedingly surprising and unmistakable light upon them. 
From these investigations it has become clear that the indi- 
vidual development of the adherent simple Ascidian Phallusia 
agrees in most points with that of the lowest vertebrate 
animal, namely, the Lancelet (Amphioxus lanccolatus). 


The early stages of the Ascidia possess the beginnings of the 
spinal niarrow and the spinal column (chorda dorsalis) 
lying beneath it, which are the two most essential and most 
characteristic organs of the vertebrate animal Accordingly, 
of all invertebrate animals known to us, the Tunicates are 
without doubt the nearest blood relations of the Vertebrates, 
and must be considered as the nearest relations of those 
Worms out of which the vertebrate tribe has developed. 
(Compare Plates XII. and XIII.) 

While thus different branches of the Coelomatous group 
of the Worms furnish us with several genealogical links 
leading to the four higher tribes of animals, and give us im- 
portant phylogenetic indications of their origin, the lower 
group of Acoelomi, on the other hand, show close relation- 
ships to the Zoophytes, and to the Primeval animals. The 
great phylogenetic interest of the Worm tribe rests upon this 
peculiar intermediate position. 




Tribe of Molluscs. — Fonr ClassRS of Molluscs : Lamp-shells (Spirobrancliia) ; 
Mussels (Lamellibrancliia) ; Snails (Cochlides) j Cuttle-fish (Cepha- 
lopoda). — Tribe of Star-fishes, or Echiuodernia. — Their Derivation 
from Einged Worms (Mailed Worms, or Phracthelminthes). — The 
Alternation of Generation in the Echinoderma. — Four Classes of 
Star-fish : Sea.stars (Asteridea) ; Sea.Hlies (Crinoidea) ; Sea-urchins 
(Echinidea) ; Sea-oucumbers (Holothnridea). — Tribe of Articulated 
Animals, or Arthropoda. — Four Classes of Articulated Animals ; 
Branchiata, or Crustacea, breathing through gills ; Jointed Ci-aba ; 
Mailed Crabs ; Articulata Tracheata, breathing through Air Tubes. 
Spiders (Long Spiders, Round Spiders). — Myriopods. — Insects. — Chew- 
ing and Sucking Insects. — Pedigree and History of the Eight Orders of 

The great natural main groups of the animal king- 
dom, which we have distinguished as teibes, or PHYLA 
("types " according to Bar and Cuvier), are not all of equal 
systematic importance for our phylogeny or history of the 
pedigree of the living world. They can neither be classed 
in a single series of stages, one above another, nor be con- 
sidered as entirely independent stems, nor as equal branches 
of a single family -tree. It seems rather (as we saw in the 
last chapter) that the tribe of Protozoa, the so-called primaeval 
animals, is the common radical group of the wliole animal 
kingdom. Out of the Gastrasada — which we class amonsc 


tlio Protozoa — -tlie Zoophytes and the Worms have developed, 
as two diverging branches. We must now in turn look 
upon the varied and much-branching tribe of Worms as the 
common primary group, out of which (from perfectly distinct 
branches) arose the remaining tribes, the four higher phyla 
of the animal kingdom. (Compare the Pedigree, p. 133.) 

Let us now take a genealogical look at these four higher 
tribes of animals, and try whether we cannot make out the 
most important outlines of their pedigree. Even should 
this attempt prove defective and imperfect, we shall at all 
events have made a beginning, and paved the road for 
subsequent and more satisfactory attempts. 

It does not matter in what succession we take up the ex- 
amination of the four higher tribes. For these four phyla 
have no close relationship whatever among one another, but 
have grown out from entirely distinct branches of the group 
of Worms (p. 133). We may consider the tribe of Molluscs 
as the most imperfect and the lowest in point of morpho- 
logical development. We nowhere meet among them with 
the characteristic articulation or segmented formation of the 
body, which distinguishes even the Ring-woiTQs, and which in 
the other three higher tribes — the Echinoderma, Articulata, 
and Vertebrata — is most essentially connected with the high 
development of their forms, their differentiation, and per- 
fection. The body in all Molluscs — in mussels, snails, etc. — 
is a simple non-jointed sack, in the cavity of which lie 
the intestines. The nervous system consists not of a cord 
but of several distinct (generally three) pairs of knots 
loosely connected with one another. For these and many 
other anatomical reasons, I consider the tribe of MoUuscs (in 
spite of the high physiological development of its most 


perfect fonns) to be morphologically the lowest among the 
four higher tribes of animals. 

Whilst, for reasons ah-eady given, we exclude the Moss- 
polyps, and Tunicates — which have hitherto been generally 
classed with the tribe of Molluscs — we retain as genuine 
MoUuscs the following four classes : Lamp-shells, Mussels, 
Snails, and Cuttles. The two lower classes of Molluscs, the 
Lamp-shells and Mussels, possess neither head nor teeth, 
and they can therefore be comprised under one main class, 
or branch, as headless animals (Acephala), or toothless animals 
(Anodontoda). This branch is also frequently called that 
of the clam-shells (Conehifera, or Bivalvia), because all its 
members possess a two-valved calcareous sheU. In contrast 
to these the two higher classes of MoUuscs, the snails and 
cuttles, may be represented as a second branch with the name 
of Head-bearers (Cephalophora), or Tooth-bearers (Odonto- 
phora), because both head and teeth are developed in them. 

The soft, sack-shaped body in most MoUuscs is protected 
by a calcareous shell or house, which in the Acephala (lamp- 
shells and mussel.?) consists of two valves, but in the 
Cephalophora (snails and cuttles) is generally a spiral tube 
(the so-caUed snail's house). Although these hard skeletons 
are found in large quantities in a petrified state in aU the 
neptunic strata, yet they teU us but little of the historical 
development of the tribe, which must have taken place 
for the most part in the primordial period. Even in 
the SUurian strata we find fossil remains of aU the four 
classes of Molluscs, one beside the other, and this, con- 
jointly with much other evidence, distinctly prove,, 
that the tribe of MoUuscs had then obtained a strong 
development, when the higher tribes, especially the 


Articulates and Vertebrates, had scarcely got beyond the 
beginning of their historical development. In subsequent 
periods, especially in the primary and secondary periods, 
these higher tribes increased in importance more and more 
at the expense of MoUuses and Worms, which were no match 
for them in the struggle for life, and accordingly decreased 
in number. The still living Molluscs and Worms must be 
considered as only a proportionately small remnant of the 
vast moUuscan fauna, which greatly predominated in the 
primordial and primary periods over the other tribes. (Com- 
pare Plate VI. and explanation in the Appendix.) 

No. tribe of animals shows more distinctly than do the 
Molluscs, how very different the value of fossils is in geology 
and in phjdogeny. In geology the different species of the 
fossil shells of Molluscs are of the greatest importance 
because they serve as excellent marks whereby to charac-. 
terize the different groups of strata, and to fix their relative 
ages. As far as relates to the genealogy of Molluscs, 
however, they are of very little value, because, on the one 
hand, the shells are parts of quite subordinate morphological 
importance, and because the actual development of the tribe 
belongs to the earlier primordial period, from which no 
distract fossUs have been preserved. If therefore we wish 
to construct the pedigree of MoUuscs, we are mainly de- 
pendent upon the records of ontogeny and comparative 
anatomy from which we obtain something like the follow- 
ing result. (Gen. Morph. iL Plate VI. pp. 102-116.) 

The lowest stage of the four classes of genuine MoUuscs 
known to us, is occupied by the Lamp-slieUs or Spiral-gills 
(Spirobranchia), frequently but inappropriately called Arm- 
footers (Brachiopoda), which have become attached to the 



bottom of tlie sea. There now exist but few forms of this 
class ; for instance, some species of Lingula, Terebratula, and 
others akin to them, which are but feeble remnants of the 
great variety of forms which represented the Lamp-shells in 
earlier periods of the earth's history. In the Silurian period 
they constituted the principal portion of the whole Mollusc 
tribe. From the agreement which, in many respects, 
their early stage of development presents with the Moss 
animals, it has been concluded that they have developed out 
of Worms, which were nearly related to this class. Of the 
two sub-classes of Lamp-shells, the Hinge-less (Ecardines 
must be looked upon as the lower and more imperfect, the 
Hinged (Testieardines) as the higher and more fully 
developed group. 

The anatomical difference between the Lamp-shells and 
the three other classes of Molluscs is so considerable that the 
latter may be distinguished from the former by the name of 
Otocardia. All the Otocardia have a heart with chamber 
(ventricle) and ante-chamber (auricle), whereas Lamp-shells 
do not possess the ante-chamber. Moreover, the central 
nervous system is developed only in the former (and not in 
the latter) in the shape of a complete pharyngeal ring- 
Hence the four classes of Molluscs may be grouped in the 

following manner 

I. Mollusca 
without head. 

II. Molluscs 
with head. 


1. Lamp-shells 

2. Mnasela 


3. Snails 


4. Catties 


I. Haplocardia 
(with simple heart). 

II. Otocardia 

(with chamber 

and ante-chamber 

to the heart). 


The result of these structural dispositions for the history 
of the pedigree of Molluscs, which is confirmed by palse- 
ontology, is that Lamp-sheUs stand much nearer to the 
primseval root of the "whole tribe of Molluscs than do the 
Otocardia. Probably Mussels and Snails developed as two 
diverging branches out of Molluscs, which were nearly akin 
to the Lamp-shells. 

Mussels, or Plate-giUs (Lamellibranchia), possess a bivalved 
shell like the Lamp-sheUs. In the latter, one of the two 
valves covers the back^ the other the belly of the animal ; 
whereas in Mussels the two valves lie symmetrically on the 
right and left side of the body. Most Mussels live in the sea, 
only a few in fresh water. The class is divided into two 
sub-classes, Asiphonia and Siphonida, of which the latter 
were developed at a later period out of the former. Among 
the Asiphonia are Oysters, mother-of-pearl Shells, and fresh 
water Mussels; among the Siphonida, which are character- 
ized by a respiratory tube, are the Venus-sheUs, Eazor-shells, 
and Burrowing Clams. The higher Molluscs seem to have 
developed at a later period out of those without head and 
teeth ; they are distinguished from the latter by the distinct 
formation of the head, and more especially by a peculiar 
kind of tooth apparatus. Their tongue presents a curious 
plate, armed with a great number of teeth. In our common 
Vineyard SnaU (Helix pomatia) the number of teeth amount 
to 21,000, and in the large Garden Slug (Limax maximus) 
to 26,800. 

We distinguish two sub-classes among the SnaUs (Coclilides, 
or Gasteropoda), namely, the Stump-headed and the Large- 
headed Snails. The Stump-headed Snails (Perocephala) are 
very closely alhed to Mussels (through the Tooth-shells), 




Of the 4 Classes^ 8 Sub-classes, and 21 Orders of Molluscs. 

Ci asses of 


Sub-classes of 


Orders of 

Systemaiic N'ame 
oj the Orders. 

I, Molkiscs witlwut head or teeth : Acephalaot- Anodontoda, 


I. Ecardines 

1. Stalked 

2. Flattened 

1. Ling-ulida 

2. Craniada 

Brachiopoda I H. Testicardine 


3- Fleshy armed 3. Sarcobracliia 

4. Ciilcarcous-annod 4, Sclerobracliia 



Lamellibrancliia ] 
or j 


III. Asiphonia 

Mussels wiihaut re- 

spiratory tiUies 


5. One-muscled 
Uneven -miisoled 
Even- muscled 

IV. Siphonida 

MusseU with respt 

raiory tubes 


S. TJound-mnntled 
9. Bay-mantled 
10. Tube-mussels 

5. IMonomya 

6. Heteromya 

7. Isornya 

8. Intcg;ripalUata 

9. Siuupalliata 
10. Indus a 

II. Molluscs with head and teeth: Cephalophora or Odontophora. 






V. Stump -headed 

VI. Larg^e-headed 

fll. Tul 
'112. Bui 


11. Scaphopoda 

12. Pfceropoda 

/IS. With hind gills 

1 14. With lore gills 

( 15. Swimming:- snails 

1 16. Beetle-Bnaila 

Vl7. Saails with lungs 17. Fulmonata 

13. Opisthobranchia 

14. Progobranchia 

15. Heteropoda 

16. Chiton oida 


VII. Chamber-Poulps /"IS. Pearl boats 18. Nautitida 

with four gills i 19. Ammon's horns 19. Auimonitida 

Tetrabranchia \ 


VIII. Ink-Poulps with ^20. Ten-armed 
two gills -I 

Dlhranchia (21. Eight-armed 

20. Dccabrachionea 

21. Octobrachionea 












(Cuttles or ^OUlps) 















(MoUnscs with chamber and ante- 
chamber to the heart) 

Promollusca (Prixaa^yal Molluscs 
Molluscs with simple heart 




and also to the Cuttle -fish (through the Butterfly-snails). 
The more highly developed Snails, "with large heads 
(Delocephala), can be divided into Snails with gills 
(Branchiata) and Snails with lungs (Pulmonata). Among 
the latter are the Land-snails, the only Molluscs which have 
left the water and become habituated to a life on land. 
The great majority of Snails live in the sea, only a few live 
in fresh water. Some River-snails in the tropics (the 
Ampullaria) are amphibious, living sometimes on land, 
sometimes in water, and at one time they breathe through 
gills, at another through lungs. They have both kinds of 
respiratory organs, like the Mud-fish and Gilled Newts 
among the Vertebrata. 

The fourth and last class, and at the same time the most 
highly developed class of Molluscs, is that of the Cuttles, or 
Poulps, also called Cephalopoda (foot attached to the head). 
They all live in the sea, and are distinguished from Snails 
by eight, ten, or more long arms, which surround the mouth 
in a circle. The Cuttles existing in our recent oceans — the 
Sepia, Calamary, Argonaut, and Pearly Nautilus — are, like 
the few Spiral-gill Lamp-shells of the present time, but a 
■poor remnant of the host which represents this class in the 
oceans of the primordial, primary, and secondary periods. 
The numerous fossil "Ammon's horns" (Ammonites), "pearl 
boats " (Nautilus), and " thunderbolts " (Belemnites) are evi- 
dences -of the long since extinct splendour of the tribe. 
The Poulps, or Cuttles, have probably developed out of a 
low branch of the snail class, out of the Butterfly-snails 
(Pteropoda) or kindred forms. 

The different sub-classes and orders, distinguished in the 
four classes of Molluscs, whose systematic succession is 


given on the Table (p. 160), furnish various^ proofs of the 
validity of the law of progress by their historical develop- 
ment and by the systematic development corresponding to it. 
As however these subordinate groups of Molluscs are in 
themselves of no further special interest, I must refer to the 
sketch of their pedigree on p. 161, and to the detailed 
pedigree of Molluscs which I have given in my General 
Morphology, and I shall now at once turn to the consider- 
ation of the tribe of Star-fishes. 

The Star-fishes (Echinoderma, or EstrellEe) among which 
are the four classes of Sea-stars, Sea-lihes, Sea-urchins, and 
Sea-cucumbers are one of the most interesting divisions of 
the animal kingdom, and yet we know less about them 
than about any. They all live in the sea. Every one who 
has been at the sea shore must have seen at least two of 
their forms, the Sea-stars and the Sea-urchins. The tribe of 
Star-fishes must be considered as a completely independent 
tribe of the animal kingdom on account of its very peculiar 
organization, and must be carefully distinguished from the 
Animal-plants — Zoophytes, or Coelenterata, with which it is 
stni frequently but erroneously classed under the name 
Radiata (as for example, by Agassiz, who even to this day 
defends this error of Cuvier's, together with many others). 

All Echinoderma are characterized, and at the same time 
distinguished from all other animals, by a very remark- 
able apparatus for locomotion, which consists of a compli- 
cated system of canals or tubes, filled with sea water from 
without. The sea water in these aqueducts is moved partly 
by the strokes of the cilia, or vibratile hairs lining their 
walls, and partly by the contractions of the muscular walls 
of the tubes themselves, which resemble india-rubber bags. 


The water is pressed from the tubes into a number of 
little hollow feet, which thereby become widely distended, 
and are then employed for walking and suction. The 
Sea-stars are moreover characterized by a peculiar cal- 
careous formation in the skin, which in most cases foi'ms 
a firm, well-closed coat of mail, composed of a number of 
plates. In almost all Echinoderma the body consists 'of 
five radii (counterparts, or antimera) standing round the 
main axis of the body, where they meet. It is only in some 
species of Sea-stars that the number of these radii amount 
to more than five — to 6 — 9, 10 — 12, or even to 20 — 40 ; 
and in this case the number of radii is generally not constant, 
but varies in different individuals of one species. 

The historical development and the pedigree of the 
Echinoderma are completely revealed to us by their 
numerous and, in most cases, excellently preserved fossil 
remains, by their very remarkable individual develop- 
mental history, and by their interesting comparative ana- 
tomy ; this is the case with no other tribe of animals, even 
the Veiiebrata themselves are not to be excepted. By a 
critical use of those three archives, and by a careful com- 
parison of the results derived from their study, we obtain 
the following genealogy of the Star-fishes, which I have 
already published in my General Morphology (vol. ii 
Plate IV. pp. G2-77.) 

The most ancient and original group of the Star-fishes, 
the primary form of the whole phylum, consists of the class 
of the true Sea-stars (Asterida). This is established by 
numerous and important arguments in anatomy and the 
history of development, but above aU by the irregular and 
varying number of the radii, or antimera, which in all other 


Echinoderma is limited, without exception, to five. Every 
Star-fish consists of a central, small, body-disc, aU round 
the circumference of which are attached five or several 
long articulated arms. Each arm of the Star-fish essentially 
coi-responds in its organization with an articulated worm 
of the class of Kiag-worms, or Annelida (p. 149). I therefore 
consider the Star-fish as a genuine stock or cormus of 
five or more articulated worms, which have arisen by the 
star-wise growth of a number of buds out of a central 
mother-worm. The connected members, thus grouped like 
the rays of a star, have inherited from the mother-worm 
the common opening of the mouth, and the common diges- 
tive cavity (stomach) lying in the central body-disc. The 
end by which they have grown together, and which fuses 
in the common central disc, probably corresponds to the 
posterior end of the original independent worms. 

In exactly the same way several individuals of certain 
kinds of worms are united so as to form a star-like cormus. 
This is the case in the Botryllidoi, compound Aseidians, 
belonging to the class of the Tunicata. Here also the pos- 
terior ends of the individual woims have grown together, 
and have formed a common outlet for discharges, a central 
cloaca ; whereas at the anterior end each worm stiU pos- 
sesses its own mouth. In Star-fishes the original mouths 
have probably become closed in the course of the historical 
development of the cormus, or colony, whereas the cloaca 
has developed into a common mouth for the whole cormus. 

Hence the Star-fishes would be compound stocks of 
worms which, by the radial formation of buds, have 
developed out of true articulated worms, or Annelids. This 
hypothesis is most strongly supported by the comparative 



Of ilie 4 Classes, 9 Sub-classes, and 20 Orders of Star-fisJies. 

(Compare Gen. IMorph 

U. Plate IV. pp. 02-or.) 

Classes of the 

Sub-classes of the 

Orders of the 

Systematic Name 




of the Orders. 



1. Primary Stars 

1. Tecastra 

Sea Stars with ra- _ 

2. Articulated Stars 

2. Colastra 

I. I 

diated stomach 

3. Brisinga Stars 

3. Brising- 

.Sta Stars < 



Asterida i 


4. Serj^ent Stars 

4. Ophiastra 


Sea Stars with disc-n 

5. Tree Stars 

5. Phytastra 


shaped stomach 

6. Lily Stars 

G. Crinastra 



1. Plated Lilies with 

7. Phatnocri. 

Lilies with arms h 

8. Articulated Lilies 
with arms 

8. Colocrinida 

II. 1 


9. Regularly budding 

9. Pentremi. 

SealLilus / 

Lilies with buds 





10. Lilies budding on 

10. Eleuthero- 

two sides 


Bladder Lilies 

11. Bladder Lilies 

11. Agelacri- 

without stalks 




12. Bladder Lilies 
with stalks 

12. Sphseroni- 

/13. Palechiiiida with 

13. Melonllida 



more than 10 


Older Sea Urchins 

rows of ambu- 


(with more than - 

lacral plates 

III. 1 

20 rows of plates) 

14. Palechinida with 

14. Eocidaria 


10 rows of am- 
\ bnlacral plates 

&ca aitcljms ^ 

Ecliinida 1 


15. Autechinida with 

15. Desmo- 


More recent Sea 

band-like am- 



Urchins (with 20 . 



rows of plates) 

16. Autechinida with 

16. Petalo- 


^ leaf-like ambulacra 



17. Enpodia with scu. 

L7. Aspidochi- 

IV. ! 

Sea Cucumbers 

with aquatic feet ■ 


tiform tentacles 
18. Enpodia with 

branching ten- 


-8. Dendrochi- 


Sfa Ct«um6cvs< 


Holothuriae * 

Sea Cucumbers 

19. Apodia with water- 

19. Lioderma- 


without aquatic 




20. Apodia without 

20. Syuaptida 
































Brahiata Fentremitida 









anatomy, and by the ontogeny of some Star-fishes (Co- 
lastra), and of segmented worms. The many -jointed Ring- 
worms (Annelida) in their inner structure are closely 
allied to the individual arms or radii of the Star-fishes, 
that is to the original single worms, which each arm 
represents. Each of the five worms of the Star-fish is 
a chain composed of a great number of equi-formal mem- 
bers, or metamera, lying one behind the other, like 
every segmented Worm, and every Arthropod. As in 
the latter a central nervous cord, the ventral nerve cord 
runs along the central line of the ventral wall of each seg- 
ment. On each metameron there is a pair of non-jointed 
feet, and besides these, in most cases, one or more hard 
thorns or bristles similar to those of many Ring-worms. 
A detached ann of a Star-fish can lead an independent hfe, 
and can then, by the radially -directed growth of buds at 
one end, again become a complete star. 

The most important proofs, however, of the truth of 
my hypothesis are furnished by the ontogeny or the 
individual development of the Echinoderma. The most 
remarkable facts of this ontogeny were first discovered 
in the year 1848 by the great zoologist, Johannes Miiller 
of Berlin. Some of its most important stages are repre- 
sented on Plates VIII. and IX. (Compare their explanation 
in the Appendix.) Fig. A on Plate IX. shows us a com- 
mon Sea-star (Uraster), Fig. B, a Sea-lily (Comatula), 
Fig. C, a Sea-urchin (Echinus), and Fig. D, a Sea-cucumber 
(Synapta). In spite of the extraordinary diflference of 
form manifested by these four representatives of the differ- 
ent classes of Star-fishes, yet the beginning of their develop- 
ment is identical in all cases. Out of the egg an animal-form 


develops wliicli is utterly different from the fully developed 
Star-fish, but very like the ciliated larvse of certain seg- 
mented Worms (Star-worms and Eing-worms). This peculiar 
animal-form is generally called the " larva/' but more cor- 
rectly the " nurse " of these Star-fish. It is very small and 
transparent, swims about by means of a fringe of cilia, 
and is always composed of two equal symmetrical halves 
or sides. The fully grown Echinoderm, however — which 
is frequently more than a hundred times larger, and quite 
opaque — creeps at the bottom of the sea, and is always 
composed of at least five co-ordinate pieces, or antimera, in 
the form of radiL Plate VIII. shows the development of the 
" nurses " of the four Echinoderms represented on Plate IX. 
The fully developed Echinoderm arises by a very remark- 
able process of budding in the interior of the " nurse," of 
which it retains little more than the stomach. The nurse, 
erroneously called the " larva," of the Echmoderm, must 
accordingly be regarded as a solitary worm, which by 
internal budding produces a second generation, in the form 
of a stock of star-shaped and connected worms. The whole 
of this process is a genuine alternation of generations, or 
metagenesis, not a " metamorphosis," as is generally though 
erroneously stated. A similar alternation of generations 
also occurs in many other worms, especially in some star 
worms (Sipunculidse), and cord worms (Nemertinae). 
Now if, bearing in mind the fundamental law of biogeny, 
we refer the ontogeny of Echinoderma to their phylogeny, 
then the whole historical development of the Star-fishes 
suddenly becomes clear a,nd intelligible to us, whereas 
without this hypothesis it remains an insoluble mystery. 
(Compare Gen. Morph. ii. pp. 95-99.) 


Besides the reasons mentioned, there are many other facts 
(principally from the comparative anatomy of Echinoderma) 
which most distinctly prove the correctness of my hypothesis. 
I established this hypothesis in ISGG, without having any 
idea that fossil articulated worins still existed, apparently 
answering to the hypothetical pi'imary forms. Such have 
in the mean time, however, really been discovered. In 
a treatise " On the Equivalent of the North American 
Taconic Schist in Germany,"* Geinitz and Liebe, in 1867, 
have described a number of articulated Silui-ian worms, 
which completely confirm my suppositions. Numbers of 
these very remarkable worms are found in an excel- 
lent state of preservation in the slates of Wiirzbach, in the 
upper districts of Eeusz. They are of the same structure 
as the articulated arm of a Star-fish, and evidently possessed 
a hard coat of mail, a much denser, more solid cutaneous 
skeleton than other worms in general. The number of 
body-segments, or metamera, is very considerable, so that 
the worms, although no more than a quarter or half an 
inch in breadth, attained a length of from two to three feet. 
The excellently preserved impressions, especially those of 
the Phyllodocites thuringiaeus and Crossopodia Hcmici, are 
so like the arms of many Star-fish (Colastra) that their 
true blood relationship seems very probable. This primae- 
val gioup of worms, which are most probably the ancestors 
of Star-fish, I call Mailed worms (Phracthelminthes, p. 150.) 

The three other classes of Echinoderma evidently arose 
at a later period out of the class of Sea-stars which have 
most faithfully retained the original form of the stellate 

* " Ucbor ein Aequivaleut der takonisoliea ScMefer Nordamerikaa in 

PI. viii. 


PI. ix. 



colony of "worms. The Sea-lilies, or Crinoida, differ 
least from them, but having given up the free, slow motion 
possessed by other Sea-stars, they have become adherent to 
rocks, etc., and form for themselves a long stalk. Some 
Encrinites, however (for example, the Comatulse, Fig. B, 
on Plates VIII. and IX.), afterwards detach themselves from 
their stalk. The original worm individuals in the Crinoida 
are indeed no longer preserved in the same independent 
condition as in the case of the common star-fish ; but they 
nevertheless always possess articulated arms extending from 
a common central disc. Hence we may unite the Sea-lilies 
and Sea-stars into a main-class, or branch, characterized as 
possessing articulated arms (Oolobrachia). 

In the other two classes of Echinoderma, the Sea- 
urchins and Sea-cucumbers, the articulated arms are no 
longer present as independent parts, but, by the increased 
centralization of the stock, have completely fused so as to 
form a com^mon, inflated, central disc, which now looks like 
a simple box or capsule without arms. The original stock 
of five individuals has apparently degenerated to the form- 
value of a simple individual, a single person. Hence we 
may represent these two classes as a branch character- 
ized as being without arms (Lipobrachia), eqiiivalent to 
those which possess articulated arms. The first of these 
two classes, that of Sea-urchins (Echinida) takes its name 
from the numerous and frequently very large thorns which 
cover the hard shell, which is itself artistically built up of 
calcareous plates. (Fig. G, Plates VIII. and IX.) The funda- 
mental form of the shell itself is a pentagonal pyramid- 
The Sea-urchins probably developed directly out of the 
group of Sea-stars. The different classes and orders of 


marine lilies and stars which are given in the following 
table, illustrate the laws of progress and differentiation in a 
striking manner. In each succeeding period of the earth's 
history we see the individual classes continually increasing 
in variety and perfection. (Gen. Morph. ii. Plate IV.) 

The history of three of these classes of Star-fish is very 
minutely recorded by numerous and excellently preserved 
fossUs, but on the other hand, we know almost nothing of 
the historical development of the fourth class, that of the 
Sea-cucumbers (HolothuriEe). These curious sausage-shaped 
Star-fish manifest externally a deceptive similarity to 
worms. (Fig. B, Plates VIII. and IX.) The skeletal struc- 
tures in their skin are very imperfect, and hence no distinct 
remains of their elongated, cylindrical, worm-like body could 
be preserved ia a fossil state. However, from the compara- 
tive anatomy of the Holothurias, we can infer that they 
have arisen, by the softening of the cutaneous skeleton, 
from members of the class of Sea-urchins. 

From the Star-fish we turn to the fifth and most highly 
developed tribe of the invertebrate animals, namely, the 
phylum of Articulata, or those with jointed feet (Arthro- 
toda). As has already been remarked, this tribe corresponds 
to Linnaeus' class of Insects. It contains four classes: 
(1) the genuine six-legged Insects, or Flies ; (2) the eight- 
legged Spiders; (3) the Centipedes, with numerous pairs 
of legs ; and (4) the Crabs, or Crustacea, whose legs vary in 
nomber. The last class breathe water through giUs, and may 
therefore be contrasted as the main-class of giU-breathincr 
Arthropoda, or Gilled Insects (Carides), with the three first 
classes. The latter breathe air by moans of pecuhar wind- 
pipes, or tracheae, and may therefore appropriately be united 


to form the main-class of the trachea-breathing Arthropoda, 
or Tracheate Insects (Tracheata). 

In aU animals with articulated feet, as the name indicates 
the legs are distinctly articulated, and by this, as well as by 
the strong differentiation of the separate parts of the body, 
or metamera, they are sharply distinguished from Ringed 
worms, with which Bar and Cuvier classed them. They 
are, however, in every respect so like the Ringed worms 
that they can scarcely be considered altogether distinct 
from them. They, like the Ringed worms, possess a very 
characteristic form of the central nervous system, the so- 
called ventral marrow, which commences in a gullet-ring 
encircling the mouth. From other facts also, it is evident 
that the Arthropoda developed at a late period out of 
articulated worms. Probably either the Wheel Animalcules 
or the Ringed worms are their nearest blood relations in 
the Worm tribe. (Gen. Morph. ii Plate V. pp. 85-102.) 

Now, although the derivation of the Arthropoda from 
ringed Worms may be considered as certain, still it cannot 
with equal assurance be maintained that the whole tribe of 
the former has arisen out of one branch of the latter. For 
several reasons seem to support the supposition that the 
Gilled Arthropods have developed out of a branch of articu- 
lated worms, different from that which gave rise to the 
Tracheate Arthropods. But on the whole it remains more 
probable that both main-classes have arisen out of one and 
the same group of Worms. In this ease the Tracheate Insects 
— Spiders, Flies, and Centipedes — must have branched off at 
a later period from the gill-breathing Insects, or Crustacea. 

The pedigree of the Arthropoda can on the whole be 
clearly made out from the palaeontology, comparative ana- 


tomy, and ontogeny of its four classes, although here, as 
everywhere else, many details remain very obscure. Not 
until the history of the individual development of all the 
different groups has become more accurately known than it 
is at present, can this obscurity be removed. The history 
of the class of GUled Insects, or Crabs (Carides), is at present 
that best known to us ; they are also called encrusted ani- 
mals (Crustacea), on account of the hard crust or covering of 
their body. The ontogeny of these animals is extremely 
interesting and, like that of Vertebrate animals, distinctly 
reveals the essential outlines of the history of their tribe, 
that is, their phylogeny. Fritz MiiUer, in his work, " Fiir 
Darwin," ^^ which has akeady been referred to, has 
explained this remarkable series of facts in a very able 

The common primary form of all Crabs, which in most 
cases is even now the first to develop out of the egg, is 
originally one and the same, the so-called Nauplius This 
remarkable primsBval crab represents a very simple form of 
articulated animal, the body of which in general has the 
form of a roundish, oval, or pear-shaped disc, and has on its 
ventral side only three pairs of legs. The first of these is 
uncloven, the two subsequent pairs are forked. In front, 
above the mouth, lies a simple, single eye. Although the 
diflferent orders of the Crustacean class diflier very widely 
from one another in the structure of their body and its 
appendages, yet the early Nauplius form always remains 
essentially the same. In order to be convinced of this, let 
the reader look attentively at Plates X. and XL, a more de- 
tailed explanation of which is given in the Appendix On 
Plate XI. we see the fully developed representatives of six 


JSazipUus-lSu^-form, of sir Crab- fish. 

Adxdtfbmn of -die same six Crab-rish. 


A. Limnetis. 
E. Cjclops . 
C. Lemacocera 
I) Lepas , 

E. SaccuIiTia. 

F. Peneus . 


different orders of Crabs, a Leaf-footed Crab (Limnetis, 
Fig. A c) ; a, Stalked Crab (Lepas, Fig. D c); a, Eoot Crab, 
(Sacculina, Fig. JE c); a, Boatman Crab (Cyclops, Fig. Be) ; a, 
Fisb Louse (Lernseocera, Fig. C c) ; and^ lastly, a bighly 
developed Shrimp (Peneus, Fig. F c) These six crabs vary 
very much, as we see, in the entire form of body, in the 
number and formation of the legs, etc. When, however, we 
look at the earliest stages, or " nauplius," of these six different 
classes, after they have crept out of the egg — those marked 
with corresponding letters on Plate X. (Fig. A n — F n) — we 
shall be surprised to find how much they agree. The differ- 
ent forms of Nauplius of these six orders differ no more 
from one another than would six different " good species " 
of one genus. Consequently, we may with assurance infer a 
common derivation of aU those orders from a common 
Primaeval Crab, which was essentially like the Nauplius of 
the present day. 

The pedigree on p. 177 will show how we may at 
present approximately conceive the derivation of the 
twenty orders of Crustacea enumerated on p. 176, from the 
common primary form of the Nauplius. Out of the Nauplius 
form — which originally existed as an independent genus — 
the five legions of lower Crabs developed as diverging 
branches in different directions, which in the systematic 
survey of the class are united as Segmented Crabs (Entomos- 
traca). The higher division of Mailed Crabs (Malaeostraca) 
have likewise originated out of the common Nauplius form. 
The Nebalia is still a direct form of transition from the 
PhyUopods to the Schizopods, that is, to the primary form 
of the stalk-eyed and sessile-eyed Mailed Crabs. The 
Nauplius at this stage gives rise to another larva form. 




Of the 7 Legions and 20 Orders of Crabs, or Crustacea. 

Legions of the 

Orders ff the 

Systema N'ame 
of the Orders. 

Name of a 

Genus as an 


L Entomostraca, Lower Crustacea, or Segmented Crabs (uot parsing through the 
actual Zoea form in youth). 

I. Branchiopoda 
Gill-footed Crabs 

1. Primaeval Crabs 

2. Leaf-foot Crabs 

3. Trilobites 

4. Water Fleas 

V 5. Elvalve Crabs 

II. Fectostraoa 
Fixed Crabs 


6. Bamaole Crabs 
Root Crabs 

1. ArcMcarida Nanplins 

2. Phyllopoda Limnetis 

3. Trilobita Paradoxides 

4. Cladocera Daphnia 

5. Ostracoda Cypria 

6. Cirripedia Lepaa 

7. Ehizocepliala Saocnlina 

III. Copepoda ( 8. Boatmen Craba 
Oar -footed Crabs 1 9. Flah Lice 

IV. Pantopoda t^^ j^^_^„3y grabs 
No-body Crabs 1 

V. Poecilopoda 
Shield Crabs 

11. Spear.tails 

12. Giant Crabs 

8. Encopepoda Cyclops 

9. Siplionostoma Lemaeocera 

10. Pyonogonida Nymphon 

11. Xiphosnra Litrmlus 

12. Gigantostraoa Enrypterns 

IL Malacostkaca, Higher Crustaom, or Mailed Crab3 (passing through the Zoea form 

in youth). 

V . Podoph- /13. Zoea Crabs 13. ZoSpoda Zoea 

thalma 14. Split-legged Craba 14. Schizopoda Mysis 

Stalk.oyedMailed 1 15. Moatli-footedCrabs 15. Stomatopoda Sqnilla 

Crabs \16. Ten-footed Crabs 16. Decapoda Penens 

VII. Zdriopli- /17. Cutaa Crabs 
thabna J 18. Flea Crabs 

MaOcdCrabswith 1 19. Wizard Crabs 
sessile eyes \,20. Louse Crabs 

17. Cumacea Cuma 

18. Araphipoda Gamraarns 

19. La3inodipoda Caprella 

20. Isopoda Oniscus 








Deoapoda Stomatopoda 








Trilobita - 





I Eliizoccpliala 

I Slphonostoma | 

Zoiia CimpedisD 







(Articulated Worms) 


the so-called Zoea, which is of great importance. The order 
of Schizopoda, those with cloven feet (Mysis, etc.), probably 
originated from this curious Zoea ; they are at present still 
directly allied, through the Nebalia to the Phyllopoda, those 
v/ith foliaceous feet. But of all living crabs the Phyllopods 
are the most closely allied to the original primary form of 
the ISTauplius. Out of the Schizopoda the stalk-eyed and 
sessile-eyed Mailed Crabs, or Malaeostraca, developed as 
two diverging branches in different directions : the former 
through shrimps (Peneus, etc.), the latter through the Cu- 
macea (Cuma, etc.), which are stUl living and closely allied 
to the Schizopoda. Among those with stalked eyes is the 
river crab (cray-fish), the lobster, and the others with long 
tails, or the Macrura, out of which, in the chalk period, the 
short-tailed crabs, or Brachyura, developed by the degenera- 
tion of the tail Those with sessile eyes divide into the 
two branches of Flea-crabs (Amphipoda) and Louse-crabs 
(Isopoda); among the latter are our common Eock-slaters 
and Wood-lice. 

The second main-class of Articulated animals, that of the 
Tracheata, or air-breathing Tracheate Insects* (Spiders, Cen- 
tipedes, and Flics) did not develop until the beginning of 
the palasolithic era, after the close of the archilithic period, 
because all these animals (in contrast with the aquatic crabs) 
are originally inhabitants of land. It is evident that the 
Tracheata can have developed only after the lapse of the 
Silurian period when terrestrial life first began. But as fossil 
remains of spiders and insects have been found, even in the 

* The English word "Insects" might vrith advantage be used in the 
Linnasan sense for the whole group of Arthropods. In this case the 
Hexapod Insects might he spoken of as the Flies. — E. R. L. 


carboniferous beds, we can pretty accurately determine the 
time of their origin. The development of the first Tracheate 
Insects out of gill-bearing Zoea-crabs, must have taken place 
between the end of the Silurian and the beginning of the 
coal period, that is, in the Devonian period. 

Gegenbaur, in his excellent " Outlines of Comparative 
Anatomy," ^^ has lately endeavoured to explain the orio-in 
of the Tracheata by an ingenious hypothesis. The system 
of tracheae, or air pipes, and the modifications of organiz- 
ation dependent upon it, distinguish Flies, Centipedes, 
and Spiders so much from other animals, that the concep- 
tion of its first origin presents no inconsiderable difficulties 
to phylogeny. According to Gegenbaur, of all hving Trache- 
ate Insects, the Primaeval Flies, or Archiptera, are most 
closel allied to the common primary form of the Tra- 
cheata. These insects — among which we may especially 
mention the delicate Day flies (Ephemera), and the agile 
dragon-flies (LibeUula) — in their earliest youth, as larvae, 
frequently possess external tracheate gills which lie in two 
rows on the back of the body, and are shaped like a leaf or 
paint-brush. Similar leaf or paint-brush shaped organs are 
met with as real water-breathing organs or gills, in many 
crabs and ringed worms, and, moreover, in the latter as real 
dorsal appendages or limbs. The " tracheate giUs," found in 
the larvae of many primaeval winged insects, must in all 
probability be explained as " dorsal limbs," and as having 
developed out of the corresponding appendages of the Anne- 
lida, or possibly as having really arisen out of similar parts 
in Crustacea long since extinct. The present tracheal 
respii'ation of the Tracheata developed at a later period out 
of respiration through " tracheate gills." The tracheate gills 


themselves, however, have in some eases disappeared, and in 
others become transformed into the vAngs of the Flies. They 
have disappeared entirely in the classes of Spiders and 
Centipedes, and these gi'oups must accordingly be conceived 
of as degenerated or peculiarly developed lateral branches of 
the Fly class, which at an early period branched off from 
the common primary form of Flies ; Spiders probably did so 
at an earlier period than Centipedes. Whether that common 
primary form of all Tracheata, which in my General Mor- 
phology I have named Protracheata, did develop directly out 
of genuine Ringed worms, or at first out of Crustacea of the 
Zoea form (Zoepoda, p. 177) will probably be settled at some 
future time by a more accurate knowledge and comparison 
of the ontogeny of the Tracheata, Crustacea, and Annelida. 
However, the root of the Tracheata, as well as that of the 
Crustacea, must in any case be looked for in the group of 
Ringed worms. 

The genuine Spiders (Arachnida) are distinguished from 
Flies by the absence of wings, and by four pairs of legs ; 
but, as is distinctly seen in the Scorpion-spiders and Taran- 
tulce, they, like Flies, possess in reality only three pairs of 
genuine legs. The apparent " fourth pair of legs" in spiders 
(the foremost) are in reality a pair of feelers. Among the 
still existing Spiders, there is a small group which is prob- 
ably very closely allied to the common primary form of the 
whole class ; this is the order of Scorpion-spiders, or Solifugae, 
(Solpuga, Galeodes), of which several large species live in 
Africa and Asia, and are dreaded on account of their poison- 
ous bite. Their body consists — as we suppose to have been 
the case in the common ancestor of the Tracheata — of a head 


possessing several pairs of feelers like legs, of a tliorax, to 
the three rings of which are attached three jjairs of legs, 
and of a hinder, body, or abdomen, consisting of many dis- 
tinct rings. In the articulation of then- body, the Solifugse 
are therefore in reality more closely related to flies than 
to other spiders. Out of the Devonian Primeeval Spiders, 
which were nearly related to the Solifugae of the present 
day, the Long Spiders, the Tailor Spiders, and the Round 
Spiders probably developed as three diverging branches. 

The Long Spiders (Arthrogastres), in which the earlier 
articulation of body has been better preserved than in Round 
Spiders, appear to be the older and more original forms. 
The most important members of this sub-class are the scor- 
pions, which are connected with the Solifugae through the 
Tarantella (or Phrynldje). The small book scorpions, 
which inhabit our libraries and herbariums, appear as a de- 
generate lateral branch from the true scorpions. Mid-way 
between the Scorpions and Round Spiders are the long- 
legged Tailor-spiders (Opiliones) which have possibly arisen 
out of a special branch of the Solifugje. The Pycnogonida, 
or ISTo-body Crabs, and the Arctisca, or Bear Worms — still 
generally included among Long Spiders — must be completely 
excluded from the class of Spiders ; the former belong to the 
Crustacea, the latter to Ringed worms. 

Fossil remains of Long Spiders are found in the Coal. 
The second sub-class of the Arachnida, the Round Spiders 
(Sphcerogastres), first appear in the fossil state in the Jura, 
that is, at a very much later period. They have developed 
out of a branch of the Solifuga, by the rings of the body 
becoming more and more united with one another. In the 


true Spinning Spiders (Aranese), which we admire on 



Of the 3 Classes and 17 Orders of the Tracheata. 

Classes of the 

Sub-Classes of Ow 

Order of the 

Two Karnes of 




Generaas examplea^ 


Scorpion spiders 

( Solpnga 
1 Galeodes 

\ ^■ 


J Phrynus 

1 Tlieljplionu3 




Long spiders 

1 3. 

Book scorpions 

( Scorpio 
1 Buthua 
( Obisinm 



1 Chelifer 

^ '■ 

Tailor spiders 

' Phalanginm 


Bound spiders ' 
» Spluerogastres 

1 6. 


Spinning spiders 

j Epeira 
\ Mygals 
J Sarcoptes 
( Demodex 



' Simple-footed 



( Scolopendra 
\ Geophilus 


or . 1 
Myri?.poda ' 





PrimitiTe flies 

( Jnlns 

(_ Polydesmna 

( Ephemei-a 


\ LibeUula 



( Hemerobins 


Chewing < 


\ Phryganea 


JFHcs i 





( Locusta 
( Forficnla 
J Cicindela 



[ Melolontha 
J Apia 
\ Formica 



C Aphis 

TI. 1 


\ Cimex 

Sucking ^ 

I 16. 



/ Culez 
1 Musca 
( Bombyx 
\ Papilio 








Gauze winga 




Tailor Spiders 


Boot Scorpions 

Primaeval Flies 

Weaving Spiders 


Scorpion Sjjidera 









Insecta Hezapoda 

Primary -Air-breathing Arthropods 

-Articulated Worms 


account of their delicate skill in weaving, the union of the 
joints of the trunk, or nietamera, goes so far, that the trunk 
now consists of only two pieces, of a head-breast (cephalo- 
thoras) with jaws, feelers, and four pairs of legs, and of a 
hinder body without appendages, where the spinning warts 
are placed. In Mites (Acarida), which have probably arisen 
by degeneration (especially by parasitism) out of a lateral 
branch of Spinning Spiders, even these two trunk pieces 
have become united and now form an unsegmented mass. 

The class of Scolopendria, Myriapoda, or Centipedes, the 
smallest and poorest in fonns of the four classes of 
Arthropoda, is characterized by a very elongated body, 
like that of a segmented Ringed worm, and often possesses 
more than a hundred pairs of legs. But these animals 
also originally developed out of a six-legged form of Trache- 
ata, as is distinctly proved by the individual development 
of the millipede in the egg. Their embryos have at fii^st 
only three pairs of legs, like genuine insects, and only 
at a later period do the posterior pairs of legs bud, one by 
one, from the growing rings of the hinder body. Of the 
two orders of Centipedes (which in our country live under 
barks of trees, in moss, etc.) the round, double-footed ones 
(Diplopoda) probably did not develop until a later period 
out of the older flat, single-footed ones (Chilopoda), by 
successive pairs of rings of the body uniting together. 
Fossil remains of the Chilopoda are first met with in the 
Jura period. 

The third and last class of the Arthropoda breathing 
through tracheae, is that of the Flies, or Insects, in the narrow 
sense of the word (Insecta, or Hexapoda), the largest of all 


classes of animals, and next to that of Mammalia, also the 
most important. Although Flies develop a greater variety of 
genera and species tlian all other animals taken together, 
yet these are all in reality only superficial variations of a 
single type, which is entirely and constantly preserved in 
its essential characteristics. In all Flies the three divisions 
of the trunk — head, breast (thorax), and hinder body — are 
quite distinct. The hinder body, or abdomen, as in the case 
of spiders, has no articulated appendages. The central divi- 
sion, the breast or thorax, has on its ventral side three pairs 
of legs, on its back two pairs of wings. It is true that, in 
very many Flies, one or both pairs of wings have become 
reduced in size or have even entirely disappeared; but 
the comparative anatomy of Flies distinctly shows that 
this deficiency has arisen only gradually by the degenera- 
tion of the wings, and that aU the Flies existing at present 
are derived from a common, primary Fly, which possessed 
three pairs of legs and two pairs of wings. (Compare p. 256.) 
These wings, which so strikingly distinguish Flies from all 
other Arthropoda, probably arose, as has been akeady shown, 
out of the tracheate gills which may stiU be observed in the 
larv33 of the ephemeral flies (Ephemera) which live in water. 
The head of Flies universally possesses, besides the eyes, 
a pair of articulated feelers, or antennae, and also three 
jaws upon each side of the mouth. These three pairs 
of jaivs, although they have arisen in all Flies from 
the same original basis, by difierent kinds of adaptation, 
have become changed to very varied and remarkable 
forms in the various orders, and are therefore employed 

for distinguishing and characterizing the main divisions 


of the class. In the first place, we may distinguish two 
main divisions, namely. Flies with clieiving mandibles 
(Masticantia) and Flies with sucJdng mouths (Sugentia). 
On a closer examination each of these two divisions may 
again be divided into two sub-groups. Among chewing 
Flies, or Masticantia, we may distinguish the biting and 
the licking ones. Biting files (Mordentia) comprise 
the most ancient and primaaval winged Flies, the gauzy- ' 
winged (Neuroptera), straight-winged (Orthoptcra), and 
beetles (Coleoptera). Licking flies (Lambentia) are re- 
presented by the one order of skin-winged (Hymenoptera) 
Flies, We distinguish two groups of Suching Flics, or 
Sugentia, namely, which prick and those which sip. 
There are two orders of pricking Flies (Pungentia), those 
with half wings (Hemiptera) and gnats and blow-flies, 
(Diptera) ; butterflies are the only sipping Flies (Sorbentia), 

Biting Flies, and indeed the order of Primceval Flies 
(Archiptera, or Pseudoneuroptera) are nearest akin to 
the still living Flies, and include the most ancient of 
all Flies, the primary forms of the whole class (hence 
also those of all Tracheata). Among them are, first of 
all, the Ephemeral Flies (Ephemera) whose larvae which 
live in water, in all probability still show us in their 
trachea3-gills the organs out of which the wings of Flies 
were originally developed. This order further contains 
the well known dragon-flics, or Libellula, the wine-glass 
sugar mites (Lepisma), the hopping Flies with bladder- 
like feet (Physopoda), and the dreaded Termites, fossil 
remains of which are found even in coal. The order 


of Gauze-winged Flies (Neuroptera), probably developed 
directly out of the primjeval Flies, which differ from them 
only by their perfect series of transformations. Among them 
are the gauze-flies (Planipennia), caddis-flies (Phryganida), 
and fan-flies (Strepsiptera). Fossil Flies, which form 
the transition from the primoeval Flies (Libellula) to 
the gauze-winged (Sialidas), are found even ia coal 

The order of Straight-winged Flies (Orthoptera) de- 
veloped at an early period out of another branch of the 
primseval Flies by differentiation of the two pairs of 
wings. This division is composed of one group with a 
great variety of forms — cockroaches, grasshoppers, crickets, 
etc. (Ulonata) — and of a smaller group consisting only of 
the well-known earwigs (Labidura), which are character- 
ised by nippers at the hinder end of their bodies. Fossil 
remains of cockroaches, as well as of crickets and grass- 
hoppers, have been found in coal. 

Fossil remains of the fourth order of Biting Flies, 
beetles (Coleoptera) likewise occur in coal. This extremely 
comprehensive order — the favourite one of amateurs and 
collectors — shows more clearly than any other what 
infinite variety of forms can be developed externally 
by adaptation to different conditions of life, without the 
internal structure and the original form of the body being 
in any way essentially changed. Beetles have probably 
developed out of a branch of the straight-winged Flies, 
from which they differ only in their transformations (larva, 
pupa, etc.) 

The one order of Licking Flies, namely, the interesting 


group of the Bees, or Skin-tvmged Flies (Hymenoptera), 
is closely allied to the four orders of biting Flies. Among 
them are those Flies which have risen to such an 
astonishing degree of mental development, of intellectual 
perfection, and strength of character, by their extensive 
division of labour, formation of communities and states, and 
surpass in this not merely most invertebrate animals, but 
even most animals in general. This may be said especially 
of all ants and bees, also of wasps, leaf- wasps, wood- wasps, 
gall-wasps, etc. They are first met with in a fossil state 
in the oolites, but they do not appear in greater numbers 
until the tertiary period. Probably these insects developed 
either out of a branch of the primseval Flies or the gauze- 
winged Flies. 

Of the two orders of PricJcing Flies (Hemiptera and 
Diptera), that containing the Half-winged Flies (Hemip- 
tera), also called Beaked Flies (Rhynchota), is the older of 
the two. It includes three sub-orders, viz., the leaf-lice 
(Homoptera), the bugs (Heteroptera), and lice (Pediculina). 
Fossil remains of the first two classes are found in the 
oolites; but an ancient Fly (Eugereon) is found in the 
Permian system, and seems to indicate the derivation of 
the Hemiptera from the Neuroptera. Probably the most 
ancient of the three sub-orders of the Hemiptera are the 
Homoptera, among which, besides the actual leaf-lice, are 
the shield-lice, leaf-fleas, and leaf-crickets, or Cicadas. Lice 
have probably developed out of two difierent branches of 
Homoptera, by continued degeneration (especially by the 
loss of wings) ; bugs, on the other hand, by the perfecting 
and differentiation of the two pairs of wings. 


The second order of pricMng files, namely, the Two- 
wimjed Flies (Diptera), are also found in a fossil state 
in the oolites, together with Half-winged Flies; but they 
probably developed out of the Hemiptera by the degenera- 
tion of the hind wings. In Diptera the fore wings alone 
have remained perfect. The principal portion of this order 
consists of the elongated gnats (Nemocera) and of the compact 
blow-flies and house-flies (Brachycera), the former of which 
are probably the older of the two. However, remains of 
both are found in the oolitic period. The two small groups 
of lice-flies (Pupipara) forming chrysales, and the hopping- 
fleas (Aphaniptera), probably developed out of the Diptera 
by degeneration resulting from parasitism. 

The eighth and last order of Flies, and at the same 
time the only one with mouth-parts adapted to sipping 
liquids, consists of moths and butterflies (Lepidoptera). 
This order appears, in several morphological respects, to 
be the most perfect class of Flies, and accordingly was 
the last to develop. For we only know of fossil remains of 
this order from the tertiary period, whereas the three 
preceding orders extend back to the oolites, and the four 
biting orders even to the coal period. The close relation- 
ship between some moths (TineEe) and (Nocture), and some 
caddis-flies (Phryganida) renders it probable that butterflies 
have developed from this group, that is, out of the order of 
Gauze-winged Flies, or Neuroptera. 

The whole history of Flies, and, moreover, the history 
of the whole tribe of Ai-thropoda, essentially confirms 
the great laws of diflerentiation and perfecting which, 
according to Darwin's theory of selection, must be 


considered as the necessary results of Natural Selection. 
The whole tribe, so rich in forms, begins in the Archilithie 
period with the class of Crahs breathing by gills, and 
with the lowest Primceval Crabs, or Archicaridse. The 
form of these Primssval Crabs, which were developed out 
of segmented worms, is still approximately preserved by 
the remarkable Nauplius, in the common larval stage of 
so many Crabs. Out of the Nauplius, at a later period, 
the curious Zoea was developed, which is the common 
larval form of all the higher or mailed crabs (Malacostraca), 
and, at the same time, possibly of that Arthopod which at 
first breathed through tracheae, and became the common 
ancestor of all Tracheata. This Devonian ancestor, which 
must have originated between the end of the Silurian 
and the beginning of the Coal period, was probably most 
closely related to the still living PrimEeval Flies, or 
Arclii'pieva. Out of these there developed, as the main 
tribe of the Tracheata, the class of Flies, from the lowest 
stage of which the spiders and centipedes separated as 
two diverging branches. Throughout a long period there 
existed only the four biting orders of Flies — -the Primseval 
flies. Gauze-wings, Straight-wings, and the Beetles, the first 
of which is probably the common primary form of the 
three others. It was only at a much later period that 
the Licking, Pricking, and Sipping flies developed out of 
the Biting ones, which retained the original form of the 
th)-ee pairs of jaws most distinctly. The following table 
will show once more how these orders succeeded one 
another in the history of the earth. 




faitlj ffiljciuincf I 



Biting Flies 



Licking Mies 

/I. Primaeval winged 

[2. Gauzo-wingod 

\ 3. Straight-winged 

4. Beetles 


I" 5, Skin-Tvinged 

I Hymenoptera, 





faitlj Sui;ktng 




Stinging Flies 


Sipping Flies 

/6. Half -winged 

I 7. Tway-flic3 

8. Butterflies 

I A. A. 



^oto. — The difference in tlie metamorphosis or transformation and in the 
development of the wings of the eight individual orders of Flies is 
specified by the following letters: M.I. = Imperfect Metamorphosis. 
M.C. = Perfect Metamorphosis. (Compare Gen. Morph. ii. p. 99.) 
A.A. = Equal wings (fore and hinder wings are tlio same, or differ but 
little). A.D. = Uiieqaal wings (fore and hinder ivinga very different in 
Btructarc and texture, occasioned by strong differentiation). 



III. Vertebuate Animals. 

Tlio Eecords of the Creation of Vertobitite Animals (Comparative Anatomy, 
Embryology, and Pakoontology) . — The Natural System of Vertebrate 
Animals. — The Fonr Classes of Vertebrate Animals, according to Lin- 
nJEUS and Lamarck. — Their increase to Nine Classes. — Main Class of the 
Tube-hearted, or Skull-less Animals (the Lancelot) — Blood Relationship 
between the Skull-less Fish and the Timicates. — Agreement in the Em- 
bryological Development of Amphioxua and Ascidiss. — Origin of tho 
Vertebrate Tribe out of the Worm Tribe. — Main Class of Single- 
nostriled, or Kound-mouthed Animals (Hag and Lampreys). — Main 
Class of Anamnionate Animals, devoid of Amnion. — Fishes (Primajval 
Fish, Cartilaginous Pish, Osseous Fish). —, orDipneusta. — Sea 
Dragons, or Halisauria.^Progs and Salmandore, or Amphibia (Mailed 
Amphibia, Naked Amphibia). — Main Class of Anmionate Animals, or 
Amniota.— Reptiles (Primary Reptiles, Lizards, Serpents, Crocodiles 
Tortoises, Flying Reptiles, Dragons, Beaked Reptiles). — Biida (Feather- 
tailed, Fan-taUed, Bush-tailed). 

Not one of the natural groups of organisms — which we have 
designated as tribes, or phyla, on account of the blood- 
relationship of all the species included in them — is of such 
great and exceeding importance as the tribe of Vertebrate 
Animals. For, according to the unanimous opinion of all 
zoologists, man also is a member of the tribe ; and his whole 
organization and development cannot possibly be distin- 
guished from that of other Vertebrate animals. But as from 


the individual history of human development, we have 
already recognized the undeniable fact that, in developing out 
of the egg, man at first does not differ from other Vertebrate 
animals, and especially from Mammals, we must necessarily 
come to the conclusion, in regard to the palseontologieal 
history of his development, that man has, historically, 
actually developed out of the lower Vertebrata, and that he 
is directly derived from lower Mammals. This circumstance, 
together with the many high interests which, in other 
respects, entitle the Vertebrata to more consideration than 
other organisms, justifies us in examining the pedigree of 
the Vertebrata and its expression in the natural system, 
with special care. 

Fortunately, the records of creation, which must in all 
cases be our guide in establishing pedigrees, are especially 
complete in this important animal tribe, from which our 
own race has arisen. Even at the beginning of our century 
Cuvier's comparative anatomy and palseontology, and Biir's 
ontoo-eny of the Vertebrate animals, had brought us to a 
high level of accurate knowledge on this matter. Since 
then it is especially due to Johannes MuUer's and Eathke's 
investigations in comparative anatomy, and most recently 
to those of Gegenbaur and Huxley, that our knowledge 
of the natural relationships among the different groups of 
Vertebrata has become enlarged. It is especially Gegen- 
baur's classical works, penetrated as they are throughout 
with the fundamental principles of the Theory of Descent, 
which have demonstrated that the material of comparative 
anatomy receives its true importance and value only by the 
application of the Theory of Descent, and this in the case 
of all animals, but especially in that in the Vertebrate tribe. 


Here, as everywhere else, analogies must be traced to Adapta- 
tion, homologies to Transmission by Inheritance. When "we 
see that the limbs of the most different Vertebrata, in spite 
of their exceedingly different external forms, nevertheless 
possess essentially the same internal structure ; when "we see 
that in the arm of a man and ape, in the wing of a man or 
a bird, in the breast fins of whales and sea-dragons, in the 
fore-legs of hoofed animals and frogs, the same bones 
ahvays lie in the same characteristic position, articulation 
and connection — we can only explain this wonderful agree- 
ment and homology by the supposition of a common trans- 
mission by inheritance from a single primary form. On 
the other hand, the striking differences of these homologous 
bodily parts' pi-oceed from adaptation to different conditions 
of existence. (Compare Plate IV.) 

Ontogeny, or the individual history of development, like 
comparative anatomy, is of especial importance to the pedi- 
gree of the Vertebrata. The first stages of development 
arising out of the egg are essentially identical in all 
Vertebrate animals, and retain their agreement the longer, 
the nearer the respective Vertebrate animal forms, when 
fully developed, stand to one another in the natural system, 
that is, in the pedigree. How far this agreement of germ 
forms, or embryos, extends, even in the most highly developed 
Vertebrate animals, I have already had occasion to explain 
(voL i. pp. 306-309). The complete agreement in form 
and structure, for example, in the embryos of a man and 
a dog, of a bird and a tortoise, existing in the stages of 
development represented on Plates II. and III., is a fact 
of incalculable importance, and furnishes us with the most 
important data for the construction of their pedigree. 


Finally, the palasontological records of creation are also 
of especial value in the case of these same Vertebrate 
animals; for their fossil remains belong for the most part 
to the bony skeleton, a system of organs which is of the 
utmost importance for understanding their general organiza- 
tion. It is true that here, as in all other cases, the fossil 
records are exceedingly imperfect and incomplete, but more 
important remains of extinct Vertebrate animals have been 
preserved in a fossil state, than of most other groups of 
animals ; and single fragments frequently furnish the most 
important hints as to the relationship and the historical 
succession of the groups. 

The name of Vertebrate Animals (Vcrtebrata), as I have 
already said, originated with the great Lamarck, who 
towards the end of the last centuiy comprised under this 
name, Linnaeus' four higher classes of animals, viz. Mammals, 
Birds, Amphibious animals, and Fishes. Linnteus' two lower 
classes, Insects and Worms, Lamarck contrasted to the 
Vertebrata as Invertebrata, later also called JEvertehrata. 

The division of the Vertebrata into the four classes above 
named was retained also by Cuvier and his followers, and 
in consequence bj-- many zoologists down to the present 
day. But in 1822 BlanviUe, the distinguished anatomist, 
found out by comparative anatomy — which Bar did almost 
at the same time from the ontogeny of Vertebrata — that 
Linna3us' class of Amphibious animals was an unnatural 
union of two very different classes. These two classes were 
separated as early as 1820, by Merrin, as two main groups 
of Amphibious animals, under the names of Pholidota and 
Batrachia. The Batracliia, which are at present (in a 
restricted sense) called Amphibious animails, comprise Frogs, 


Salamanders, gilled Salamanders, Ccecilia, and the extinct 
Labyrinthodonta. Their entire organization is closely 
allied to that of Fishes. The Flcolidota, or Reptiles, on the 
other hand, are much more closely allied to Birds. They 
comprise lizards, serpents, crocodiles, and tortoises, and 
the groups of the mesolithic Dragons, Flying reptiles, etc. 

In conformity with this natural division of Amphibious 
animals into two classes, the whole tribe of Vertebrate 
animals was divided into two main groups. The first main 
group, containing Amphibious animals and Fishes, breathe 
throughout their lives, or in early life, by means of gills, 
and are therefore called gilled Vertehrata (Branchiata, or 
Anallantoida). The second main group — Reptiles, Birds, 
and Mammals — breathe at no period of their lives through 
gills, but exclusively through lungs, and hence may appro- 
priately be called Gill-less, or Ve7'tebrata with lungs 
(Abranchiata, or Allantoida). However correct this dis- 
tinction may be, still we cannot remain satisfied with it 
if we wish to arrive at a true natural system of the verte- 
brate tribe, and at a right xinderstanding of its pedigree. In 
this case, as I have shown in my General Morphology, we 
are obliged to distinguish three other classes of Vertebrate 
animals, by dividing what has hitherto been regai-ded as 
the class of fishes into four distinct classes. (Gen. Morph. 
vol. ii. Plate VII. pp. 116-160.) 

The first and lowest of these classes comprises the Skull- 
less animals (Acrania), or animals with tubular hearts 
(Leptocardia), of which only one representative now exists, 
namely, the remarkable little Lancelet (Amphioxus lanceola- 
tus). Nearly aUied to this is the second class, that of the 
Single-nostriled animals (Monorrhina), or Round-mouthed 


animals (Cj^clostoma), 'whicli includes the Hags (Myxinoida) 
and Lampreys (Petromyzonta). The third class contains 
only the genuine Fish (Pisces) : the Mud-fishes (Dipneusta) 
are added to these as a fourth clasSj and form the transi- 
tion from Fish to Amphibious animals. This distinction, 
which, as will be seen immediately, is very important for the 
genealogy of the Vertebrate animals, increases the original 
number of Vertebrate classes from four to eight. 

In most recent times a ninth class of Vertebrata has been 
added to these eight classes. Gegenbaur's recently published 
investigations in comparative anatomy prove that the 
remarkable class of Sea-dragons (Halisauria), which have 
hitherto been included among Reptiles, must be considered 
quite distinct from these, and as a separate class which 
branched off from the Vertebrate stock, even before the 
Amphibious animals. To it belong the celebrated large 
Ichthyosauri and Plesiosauri of the oolitic and chalk periods, 
and the older Simosauri of the Trias period, all of which are 
ruore closely allied to Fish than to Amphibious animals. 

These nine classes of Vertebrate animals are, however, by 
no means of the same genealogical value. Hence we must 
divide them, as I have already shown in the Systematic 
Survey on p. 133, into four distinct main-classes or tribes. In 
the first place, the three highest classes, Mammals, Bu-ds, and 
Reptiles, may be comprised as a natural main-class under 
the name of Ainnion aniinals (Amnionata). The Avmion- 
less animals (Anamnionata), naturally opposed to them as 
a second main-class, include the four classes of Batrachians, 
Sea-dragons, Mud-fish, and Fishes. The seven classes just 
named, the Anamnionata as well as the Amnionata, agree 
among one another in numerous characteristics, which dis- 



tinguish them from the two lowest classes (the single- 
nostriled and tubular-hearted animals). Hence we may unite 
them in the natural main group of Douhle-nostriled animals 
(Amphirrhina). Finally, these Amphirrhina on the whole 
are much more closely related to those animals with round 
mouths or single nostrils than to the skuU-less or tube- 
hearted animals. We may, therefore, with fuU justice class 
the single and double-nostriled animals into one principal 
main group, and contrast them as animals with skulls 
(Craniota), or hiUhidar hearts (Pachycardia), to the one class 
of sJcull-less animals, or animals with tubular hearts. This 
classification of the Vertebrate animals proposed by mo 
renders it possible to obtain a clear survey of the nine 
classes in their most important genealogical relations. The 
systematic relationship of these groups to one another may 
be briefly expressed by the following table. 


SRulLltss animals 

1. Tabular hearts 1. Leptocardia 


Stnimals faitlj 



Cijicft Kcutts 


a. Single-nostriled 




I 2. Ronnd-moafclis 2. Cyclostoma 

b. Double , 
no st riled 


I. Non- 

II. Amniou- 



1^3. Fish 

4. Mad.ash 

5. Sea-dragons 
fi. Batracbiana 

7. Reptiles 

8. Birds 

9- Mammals 

3. Pisces 

4. Dipnensta 

5. Halisauria 

6. Amphibia 

7. Reptilia 

8. Aves 

9. Mammalia 

The only one representative of the first class, the small 
lanceolate fish, or Lancelet (Amphioxus lanceolatus) (Plate 
XIIL Fig. B), stands at the lowest stage of organization 


of all the Vertebrate animals known to us. This exceedingly 
interesting and important animal, which throws a surprising 
light upon the older roots of our pedigree, is evidently the 
last of the Mohicans — the last surviving representative of a 
lower class of Vertebrate animals, very rich in forms, and 
very highly developed during the primordial period, but 
which unfortunately could leave no fossil remains on account 
of the absence of all solid skeleton. The Lancelet still 
lives widely distributed in different seas ; for instance, 
in the Baltic, North Sea, and Mediterranean, where it 
generally lies buried in the sand on flat shores. The body, 
as the name indicates, has the form of a narrow lanceolate 
leaf, pointed at both extremities. When full grown it is 
about two inches long, of a white colour and semi-trans- 
parent. Externally, the little lanceolate animal is so little 
like a vertebrate animal that Pallas, who first discovered it, 
regarded it as an imperfect naked snail It has no legs, 
and neither head, skull, nor brain. Externally, the fore end 
of the body can be distinguished from the hinder end only 
by the open mouth. But still the Amphioxus in its internal 
structure possesses those most important features, which 
distinguish all Vertebrate animals from all Invertebrate 
animals, namely, the spinal rod and spinal marrow. The 
spinal rod (Chorda dorsalis) is a straight, cylindrical, 
cartilaginous staff, pointed at both ends, forming the cen- 
tral axis of the internal skeleton, and the basis of the 
vertebral column. Directly above the spinal rod, on its 
dorsal side, lies the spinal marrow (meduUa spinalis), like- 
wise originally a straight but internally hollow cord, pointed 
at both ends. This forms the principal piece and centre of 
the nervous system in all Vertebrate animals. (Compare above 


vol. L p. 303.) In all Vertebrate animals without exception, 
man included, these important parts of the body during 
the embryological development out of the egg, originally 
begin in the same simple form, which is retained throughout 
life by the Amphioxus. It is only at a later period that the 
brain develops by the expansion of the fore end of the spinal 
marrow, and out of the spinal rod the skull which encloses 
the brain. As these two important organs do not develop 
at all in the Amphioxus, we may justly call the class repre- 
sented by it, ShuU-less animals (Acrania), in opposition to 
all the others, namely, to the animals zvith skulls (Craniota). 
The Skull-less animals are generally called tubular -hearted 
(Leptocardia), because a centralized heart does Eot as yet 
exist, and the blood is circulated in the body by the con- 
tractions of the tubular blood-vessels themselves. The 
SkuUed animals, which possess a centralized, thick-walled, 
bulb-shaped heart, ought then by way of contrast to be 
called hulbular-hearted animals (Pachycardia). 

Animals with skulls and central hearts evidently developed 
gradually in the later primordial period out of those without 
skulls and with tubular hearts. Of this the ontogeny of 
skulled animals leaves no doubt. But whence are these 
same skull-less animals derived ? It is only very lately that 
an exceedingly surprising answer has been given to this 
important question. From Kowalewsky's investigations, 
published in 1867, on the individual development of the 
Amphioxus and the adhering Sea-squirts (Ascidia) belonging 
to the class of mantled animals (Tunicata), it has been proved 
that the ontogenies of these two entirely different looking 
animal-forms agree in the first stage of development in a 
most remarkable manner. The freely swimming larvae of the 

<ct<]f(( I .-[J <ut(J Arnffliidras {£.) 



Ascidians (Plate XII. Fig. A) develop the undeniable begin- 
ning of a spinal marrow (Fig. 5 g) and of a spinal rod (Fig. 5 c), 
and this moreover in entirely the same way as does the 
Amphioxus. (Plate XIII. Fig. B.) It is true that in the 
Ascidians these most important organs of the Vertebrate 
animal-body do not afterwards develop further. The 
Ascidians take on a retrograde transformation, become 
attached to the bottom of the sea, and develop into shape- 
less lumps, which when looked upon externally would 
scarcely be supposed to be animals. (Plate XIII. Fig. A.) But 
the spinal marrow, as the beginning of the central nervous 
sj'stem, and the spinal rod, as the first basis of the vertebral 
column, are such important organs, so exclusively character- 
istic of Vertebrate animals, that we may from them with 
certitude infer the true blood relationship of Vertebrate 
with Tunicate animals. Of course we do not mean to say 
by this, that Vertebrate animals are derived from Tunicate 
animals, but merely that both groups have arisen out of a 
common root, and that the Tunicates, of all the Invertebrata, 
are the nearest blood relations of the Vertebrates. It is 
quite evident that genuine Vertebrate animals developed 
progressively during the primordial period (and the skuU- 
less animals first) out of a group of worms, from which the 
degenerate Tunicate animals arose in another and a retro- 
grade direction. (Compare the more detailed explanation of 
Plates XII. and XIII. in the Appendix.) 

Out of the SkuU-less animals there developed, in the first 
instance, a second, low class of Vertebrate animals, which 
still stands far below that of fish, and which is now repre- 
sented only by the Hags (Myxinoida) and Lampreys 
(Petromyzonta). This class also, on account of the absence 


of all solid parts, could, unfortunatelj', as little as the 
Skull-less animals leave fossil remains. From its whole 
organization and ontogeny it is quite evident that it 
represents a very important intermediate stage between 
the Skull-less animals and Fishes, and that its few still 
existing members are only the last survivrag remains of 
a probably very highly developed animal group which 
existed towards the end of the primordial period. On 
account of the curious mouth possessed by the Hags 
and Lampreys, which they use for sucking, the whole class 
is usually called Round-Tnouthed animals (Cyclostoma). 
The name of Single-nostriled animals (Monorrhina) is still 
more characteristic. For all Cyclostoma possess a simple, 
single nasal tube, whereas, in all other Vertebrate animals 
(with the exception of the Amphioxus) the nose consists 
of two lateral halves, a right and a left nostril We are 
therefore enabled to comprise these latter (Anamnionata 
and Amnionata) under the heading, douhle-nostriled animals 
(Amphin-hina). All the Amphirrhina possess a fuUy 
developed jaw-skeleton (upper and under jaw), whereas it 
is completely wanting in the Monorrhina. 

Apai-t also from the peculiar nasal formation, and the 
absence of jaws, the Single-nostriled animals are dis- 
tinguished from those with double nostrils by many 
peculiarities. Thus they want the important sympathetic 
nervous system, and the spleen which the Amphirrhina 
possess. Of the swimming bladder, and the two pairs of legs 
— which all double-nostriled animals have, at least in their 
embryonic conditions — not a trace exists in the Single- 
nostriled animals, which is the case also in the Skull-less 
animals. Hence, we are surely justified in completely 

Ascidici (A.) and. ATnphioxiLS (B.) 






separating the Monorrhina, as w& have separated the Skull- 
less animals, from the Fishes, with which they have hitherto 
been erroneously classed. 

We owe our first accurate knowledsre of the Monorrhina, 
or Cj'clostoma, to the great zoologist, Johannes Miiller of 
Berlin; his classical work on the "Comparative Anatomy 
of the Myxinoida" forms the foundation of our modern 
views on the structure of the Vertebrate animals. He 
distinguished two distinct groups among the Cyclostoma, 
which we shall consider as sub-classes. 

The fii'st sub-class consists of the Hags (Hyperotrcta, or 
Myxinoida). They live in the sea as parasites upon other 
fish, into whose skin they penetrate (Myxine, Bdellostoma). 
Their organ of hearing has only one annular canal, and 
their single nasal tube penetrates the palate. The second 
sub-class, that of Lampreys, or Prides (Hyperoartia, or 
Petromyzontia) is more highly developed. It includes the 
well-known Lampems, or Nine-eyes, of our rivers (Petro- 
myzon fluviatilis), with which most persons are acquainted. 
They are represented in the sea by the frequently larger 
marine or genuine Lamjareys (Petromyzon marinus). The 
nasal tube of these single-nostriled animals does not 
penetrate the palate, and in the auricular organ there are 
two annular canals. 

All existing Vertebrate animals, with the exception of 
the Monorrhina and Amphioxus just mentioned, belong to 
the group which we designate as Double-nostriled animals 
(Amphirrhina). All these animals possess (in spite of the 
great variety in the rest of their forms) a nose consisting of 
two lateral halves, a jaw-skeleton, a sympathetic nervous 
system, three annular canals connected with the auricular 




Of the 4 Main-classes, 9 Glasses, and 26 Sid)-classBs of Vertehrata. 
Gen. Morph. vol. ii. Plate VII. pp. 110-100. 

I. Sfe«U4cS3 (Acrania), or Eu6c4jcatt£l> (leptocardia) . 
Vcrtebrata without head, without skull and brain, without centralized heart. 

1. SItuIMcSS I. Tabo-hearted [ i_ ^ancelet 1. Amphioxus 

II. animals toitifj slwlla (Craniota) and with tijicfesioalleli fjcatts (Pachycardia). 
Vertebrata with head, with ekoll and brain, with centralized heart. 


of the Skulled, 



of the 

Skulled Animals. 


of the 

Skulled Animals. 

Systematic Name 

of the 


2. Sinijlcs 

3. |ian=am» 




4. Stmnion 



II. Bound mouths 

III. Fish 

IV. Mud .fish 

T. Sea.dragons 

VI. Batrachiana 

VII. Roptilea 

VIII. Birds 

IX. Mammals 













Hags, or Mucous 

Lampreys, or 

Primseval fish 
Ganoid fiah 
Osseous fish 




Mailed Batra- 

Naked Batra- 

Primary reptiles 





Flying reptiles 


Beaked reptiles 



Bush- tailed 

2. Hyperotreta 

8. Hyperoartia 

4. Selachii 

5. Ganoides 

6. Teleostei 

7. Protopteri 

8. Simosanria 

9. Plesiosauria 

10. lohthyosauria 

11. Phraotamphibia 

12. Lissamphibia 

13. Tocosauria 

14. Lacertilia 

15. Opliidia 

16. Crocodilia 

17. Chelonia 

18. Pterosauria 

19. Diuosauria 

20. Anomodojitia 

21. Saurnrte 

22. CarinatsB 

23. Eatitaj 

24. Cloaca! animals 2-1.. Monotrema 

25. Pouched animals 25. Marsupialia 

26. Placental animals 2G. Placeutalia 



9. Mammals 

8. BirclB 

7. Eeptilea 

5. Sea-dragons 

OsseonB fiah 

Ganoid fish 

4. Mnd-fish 

Amnion animals 

6. BatracBians 

Vertebrate animals breathing througli lnngB 


Primaeval fish Selachii 

3. Pishes Fisces 

ID(m6k=nOStriIcS Amphirrhina 

2. Eonnd-mouthed 

Sinalc-nasttilcS Monorrhina 
animals toiti) stalls ^ Craniota 
1. Tube-hearted 



SkulHcss animals 

Ucrtcbtatc animals 





sac, and a spleen. Further, all Double-nostriled animals 
possess a bladder-shaped expansion of the gullet, which, in 
Fish, has developed into the swimming bladder, but in all 
other Double-nostriled animals into lungs. Finally, in all 
Double-nostriled animals there exist in the youngest stage 
of growth the beginnings of two pairs of extremities, or 
limbs, a pair of fore legs, or breast fins, and a pair of hinder 
legs, or ventral fins. One of these pairs of legs sometimes 
degenerates (as in the case of eels, whales, etc.), or both 
pairs of legs (as in Csecilias and serpents) either degenerate 
or entirely disappear ; but even in these cases there exists 
some trace of their original beginning in an early embryonic 
period, or the useless remains of them may be found in the 
form of rudimentary organs. (Compare above, vol. i. p. 13.) 

From aU these important indications we may conclude 
with fuU assurance that aU double-nostriled animals are 
derived from a single common primary form, which 
developed either directly or indirectly during the primordial 
period out of the Monorrhina. This primary form must 
have possessed the organs above mentioned, and also the 
beginning of a swimming bladder and of two pairs of legs 
or fins. It is evident, that of all still living double-nostriled 
animals, the lowest forms of sharks are most closely allied 
to this long since extinct, unknown, and hypothetical 
primary form, which we may call the Primary Double- 
nostriled animals (Proselachii). We may therefore look 
upon the group of primeeval fish, or Selachii, to which the 
Proselachii probably belonged, as a primary group, not 
only of the Fish class, but of the whole main-class of double- 
nostriled animals. 

The class of Fish (Pisces) with which we accordingly 


begin the series of Double-nostriled animals, is distinguislied 
from the other six classes of the series by the swimming 
bladder never developing into lungs, but acting only as a 
hydrostatic apparatus. Agreeing with this, we find that 
in fish the nose is formed by two blind holes in front of 
the mouth, which never pierce the palate so as to open 
into the cavity of the mouth. In the other six classes of 
double-nostriled animals, both nostrils are changed into air 
passages which pierce the palate, and thus conduct air 
to the lungs. Genuine fish (after the exclusion of the 
Dipneusta) are accordingly the only double-nostriled 
animals which exclusively breathe through giUs and never . 
through lungs. In accordance with this, they aU live in 
water, and both pairs of their legs have retained the original 
form of paddling fins. 

Genuine fish are divided Into three distinct sub-classes, 
namely. Primaeval fish. Ganoid fish, and Osseous fiah. 
The oldest of these, where the original form has been most 
faithfully preserved, is that of the Frimceval fish (Selachii). 
Of these there still exist Sharks (Squali), and Rays 
(Rajoe), which are classed together as cross-mouthed fishes 
(Plagiostomi), and the strange and grotesquely formed Sea- 
cats, or Chirnmracei (Holocephali). These primary fish of 
the present day, which are met with in all seas, are only 
poor remains of the prevailing animal groups, rich in forms, 
which the Selachii formed in the earlier periods of the 
earth's history, and especially during the palaeolithic period. 
Unfortunately all Primseval fish possess a cartilaginous, 
never a completely osseous skeleton, which is but little, if 
at all, capable of being petrified. The only hard parts of 
the body which could be preserved in a fossil state, are the 



Of the- 7 Legions and 15 Orders of the Fishes. 









the Orders. 

^ ( 

|3timffiwl ^ 


I. Transverse 


' 1. 



Sharks, dog-fish 

Spiked rays, electric 
rays, etc. 


II. Sea-Cata 



Chimoora, Calorrhyn- 


^ MolocepliaU 



III. Mailed Ganoid 
Pish ^ 

■ 4. 




Cephalaspidse, Placo- 

derma, etc. 
Spoon-sturgeons, stur- 



gecns, sterlet, etc. 





IV. Angnlar-scalcd 
Ganoid Fish ^ 






Palseoniscus, bony J)ike, 

African finny pike, 


Y. Ronnd-scaled 

Ganoid Fish 


■ 9. 


Iloloptychius, Coelacan- 

thides, etc. 
Coccolepida, Amiadas, 





'VI. Osseons Fish 

with an air 

passage to the 




VII. Osseous Fish 

without an air 




Herring species 
Eol species 


Herrings, salmon, carp, 

Eels, snake eels, electric 

eels, etc. 

Perch, wrasse, turbot, 

passage to the 



Trunk fish, globe fish, 






Pipe fish, sea horses. 

^, Physoclisti 












Ganocephala Sozobranchia 
Fhractamphlbia Xissampliibia 



































teeth and fin-spikes. These are found in the older 
formations in such quantities, varieties, and sizes, that we 
may, with certainty, infer a very considerable develop- 
ment of Primaeval fish m those remote ages. They are even 
found in the Silurian strata, which contain but few 
remains of other Vertebrata, such as Enamelled fish (and 
these only in the most recent part, that is, in the upper 
Silurian). By far the most important and interesting of 
the three orders of Primreval fish are Sharks; of all still 
living double-nostriled animals, they are probably most 
closely allied to the original primary form of the whole 
group, namely, to the Proselachii. Out of these Proselachii, 
which probably differed but little from genuine Sharks, 
Enamelled fish, and the present Primteval fish, in all prob- 
ability, developed in one direction, and the Dipneusta, 
Sea-dragons, and Amphibia in another. 

The Ganoid, or EnatiicLled fish (Ganoldes), in regard to 
their anatomy stand midway between the Prima3val and the 
Osseous fish. In many characteristics they agree with the 
former, and in many others with the latter. Hence, we infer 
that genealogically they form the transition from Primssval 
to Osseous fish. The Ganoids are for the most part extinct, 
and more nearly so than the Primeval fish, whereas they 
were developed in great force during the entire palaeolithic 
and mesolithic periods. Ganoid fish are divided into 
three legions according to the form of their external 
covering, namely, Mailed, Angular-scaled, and Round- 
scaled. The Mailed Ganoid fish (Tabuliferi) are the oldest, 
and are directly allied to the Selachii, out of which they 
originated. Fossil remains of them, though rare, are found 
even in the upper Silurian (Pteraspis ludensis of the 


Ludlow strata). Gigantic species of them, coated v/ltli 
strong bony plates, are found in the Devonian system. 
But of this legion there now lives only the small order 
of Sturgeons (Sturiones), including the Spade-sturgeons 
(Spatularidffi), and those Sturgeons (Accipenseridse) to 
which belong, among others, the Huso, which yields isinglass, 
or sturgeon's sound, and the Caviar-sturgeon, whose eggs 
we eat in the shape of caviar, etc. Out of the mailed 
Ganoid fish, the angular and round-scaled ones probably 
developed as two diverging branches. The Angular-scaled 
Ganoid fish (Rhombiferi) — which can be distinguished at 
first sight from all other fish by their square or rhombic 
scales — are at present represented only by a few survivors, 
namely, the Finny Pike (Polypterus) in African rivers 
(especially the Nile), and by the Bony Pike (Lepidosteus) 
in American rivers. Yet during the palsgolithic and the 
first half of the mesolithic epochs this legion formed the 
most numerous group of fishes. The third legion, that of 
Round-scaled Ganoid fish (Cycliferi), was no less rich in 
forms, and lived principally during the Devonian and Coal 
periods. This legion, of which the Bald Pike (Amia), 
in North American rivers, is the only survivor, was 
especially important, inasmuch as the third sub-class of 
fish, namely. Osseous fish, developed out of it. 

Osseous fish (Teleostei) include the greater portion of the 
fish of the present day. Among these are by far the 
greater portion of marine fish, and all of our fresh-water 
fish except the Ganoid fi:h just mentioned This class 
is distinctly proved by numerous fossils to have arisen 
about the middle of the Mesolithic epoch out of Ganoid 
fish, and moreover out of the Round-scaled, or Cycliferi. 


The Thri^sopidce of the Oolitic period (Thrissops, Leptolepia, 
Tharsis), which are most closely allied to the herrings of the 
present day, are probably the oldest of all Osseous fish, 
and have directly arisen out of Round-scaled Ganoid fish, 
closely allied to the existing Amia. In the older Osseous 
fish of the legion called Pliysostomi, as also in the 
Ganoides, the swimming bladder throughout life was 
connected with the throat by a permanent air passage 
(a kind of windpipe). This is still the case with all the 
fish belonging to this legion, namely, with herrings, salmon, 
carp, shad, eels, etc. However, during the chalk period this 
air passage, in some of the Physostomi, became constricted 
and closed, and the swimming bladder was thus completely 
separated from the throat. Hence there arose a second 
legion of Osseous fish, the Physoclisti, which did not 
attain their actual development until the tertiary epoch, 
and soon far surpassed the Physostomi in variety. To this 
legion belong most of the sea fish of the present day, 
especially the large families of the Turbot, Tunny, Wrasse, 
Crowfiah, etc., further, the Lock-jaws (Plectognathi), Trunk 
fish, and Globe-fish and the Bushy -gills (Lophobranchi), viz.. 
Pipe-fish, and Sea-horses. There are, however, only very 
few Physoclisti among our river fish, for instance. Perch 
and Sticklebacks ; the majority of river fish are Physostomi. 
Midway between genuine Fish and Amphibia is the 
remarkable class of Mud-fish, or Scaly Sirens (Dipneusta, 
or Protopteri), There now exist only a few representatives 
of this class, namely, the American Mud-fish (Lepidosiren 
paradoxa) in the region of the river Amazon, and the 
African Mud-fish (Protopterus annectens) in different parts 
of Africa. A third large Salamander-fish (Ceratodus Foster!) 


has lately been discovered in Australia. During the dry 
season, that is in summer, these strange animals bury 
themselves in a nest of leaves in the dry mud, and then 
breathe air through lungs like the Amphibia. But during 
the wet season, in winter, they live in rivers and bogs, 
and breathe water through gills like fish. Externally, they 
resemble fish of the eel kind, and are hke them covered 
with scales; in many other characteristics also — in their 
internal structure, their skeleton, extremities, etc. — they 
resemble Fish more than Amphibia. But in certain features 
they resemble the Amphibia, especially in the formation 
of their lungs, nose, and heart. There is consequently an 
endless dispute among zoologists, as to whether the Mud- 
fish are genuine Fish or Amphibia. Distinguished zoologists 
have expressed themselves in favour of both opinions 
But in fact, owing to the complete blending of character- 
istics which they present, they belong neither to the one 
nor to the other class, and are probably most correctly 
dealt with as a special class of Vertebrata, forming the 
transition between Fishes and Amphibians. The still living 
Dipneusta are probably the last surviving remains of a 
group which was formerly rich in forms, but has left no 
fossil traces on account of the want of a solid skeleton. 
In this respect, these animals are exactly like the Monor- 
rhina and the Leptocardia. However, teeth are found in 
the Trias which resemble those of the living Ceratodus. 
Possibly the extinct Dipneusta of the palEeolithic period, 
which developed in the Devonian epoch out of primaeval 
fish, must be looked upon as the primary forms of the 
Amphibia, and thus also of all higher Vertebrata, At 
all events the unkno^vn forms of transition — from Primaeval 
fish to Amphibia — were probably very like the Dipneusta. 


A very peculiar class of Vertebrate animals, long since 
extinct, and which appears to have lived only during 
the secondary epoch, is formed by the remarkable Sea- 
dragons (Halisaiirla, or Enaliosauria, also called Nexipoda, 
or Swimming-footed animals). These formidable animals 
of prey inhabited the mesolithic oceans in great numbers, 
and wore of most peculiar forms, sometimes from thirty 
to forty feet in length. From many and excellently pre- 
served fossil remains and impressions, both of the entire 
body of Sea-dragons as well as of single parts, we have 
become very accurately acquainted with the structure of 
their bodies. They are usually classed among Reptiles, 
whilst some anatomists have placed them in a much lower 
rank, as directly allied to Fish. Gegenbaur's recently 
published investigations, which place the structure of their 
limbs in a true light, have led to the surprising conclusion 
that the Sea-dragons form quite an isolated group, differ- 
ing widely both from Reptiles and Amphibia as well as 
from Fish. The skeleton of their four legs, which are 
transformed into short, broad, paddling fins (like those of 
fish and whales) furnishes us with a clear proof that the 
Halisauria branched off from the main-stock of Verfcebrata at 
an earlier period than the Amphibia. For Amphibia, as well 
as the three higher classes of Vertebrata, are all derived 
from a common primary form, which possessed orAj five toes 
or fingers on each leg. But the Sea-dragons have (either 
distinctly developed or in a rudimentary condition as 
parts of the skeleton of the foot) more than five fingers, 
as have also the Selachians or Primeeval fish. On the other 
hand, they breathed air through lungs, like the Dipneusta, 
although they always swam about in the sea. They, 


therefore, perhaps, ia conjunction with the Dipnensta, 
branched off from the Selachii, but did not develop into 
higher Vertebrata ; they form an e::tinct lateral line of the 
pedigree, which has died out. 

The more accurately known Sea-dragons are classed into 
three orders, distinct enough one from the other, namely, 
PrimcGval Dragons, Fish Dragons, and Serpent Dragons. 
The PrimcBval Dragons (Simosauria) are the oldest Sea- 
dragons, and lived only during the Trias period. The 
skeletons of many different genera of them are met with 
in the German limestone known as " Muschel-kalk." They 
seem upon the whole to have been very like the 
Plesiosauria, and are, consequently, sometimes united with 
them into one order as Sauropterygia. The Serpent 
Dragons (Plesiosauria) lived in the oolitic and chalk 
periods together with the Iclithyosauria. They were 
characterised by an uncommonly long thin neck, which 
was frequently longer than the whole body, and carried 
a small head with a short snout. When their arched neck 
was raised they must have looked very like a swan ; but 
in place of wings and legs they had two pairs of short, 
flat, oval-paddling fins. 

The body of the Fish Dragons (Ichthyosauria) was of 
an entirely different form ; these animals may be opposed 
to the two preceding orders under the name of Fish- 
finners (Ichthyopterygia). They possessed a very long 
extended body, like a fish, and a heavy head with an 
elongated, flat snout, but a very short neck. Externally, 
they were probably very like porpoises. Their tail was 
very long, whereas it was very short in the members of the 
preceding orders. Also both pairs of paddling fins are 


broader and show very different structure from that seen 
in the other two orders. Probably the Fish Dragons and 
Serpent Dragons developed as two diverging branches 
out of the Primaeval Dragons ; but it is also possible that 
the Plesiosauria alone originated out of the Simosauria, 
and that the Ichthyosauria were lower off-shoots from the 
common stock. At all events, they must all be directly, or 
indirectly derived from the Selachii, or Primseval fish. 

The succeeding classes of Vertebrata, the Am])hihia and 
the A mniota (Reptiles, Birds, and Mammals), owing to the 
characteristic structure which they all exhibit of five toes 
to each foot, may all be derived from a common primary 
form, which originated from the Selachii, and which possessed 
five toes on each of its four limbs. When we find a less 
number of toes than five, we can show that the missing 
ones must have been lost in the coiirse of time by adapta- 
tion. The oldest known Vertebrata with five toes are 
the BatracJiias (Amphibia). We divide this class into 
two sub-classes, namely, mailed Batrachians and naked 
Batrachians, the first of which is distinguished by tlie body 
being covered with bony plates or scales. 

The first and elder sub-class of Amphibia consists of the 
Mailed Batrachians (Phractamphibia), the oldest land 
living Vertebrata of which fossil remains exist. Well- 
preserved fossil remains of them occur in the coal, especially 
of those with Enamelled heads (Ganoeephala), which are 
most closely allied to fish, namely, the Archegosaurus 
of Saarbruck, and the Dendi-ei-peton of North America. 
There then follow at a later period the gigantic Labyrinth- 
toothed animals (Labyrinthodonta), which are represented 
in the Permian system by Zygosaurus, but at a later 


period, more especially in the Trias, by Mastodonsaurus, 
Trematosaurus, Capifcosaurus, etc. The shape of these 
formidable rapacious animals seems to have been between 
that of crocodiles, salamanders, and frogs, but in their 
internal structure they were more closely related to the 
two latter, while by their solid coat of mail, formed of 
strong bony plates, they resembled the first animals. 
These gigantic mailed Batrachians seem to have become 
extinct towards the end of the Triassic period. No fossil 
remains of mailed Batraehia are known during the whole 
of the subsequent periods. However, the still livuig blind 
Snakes, or Ccecilice (Peromela) — small-scaled Phractamphibia 
of the form and the same mode of life as the earth-worm — 
prove that this sub-class continued to exist, and never 
became completely extinct. 

The second sub-class of Amphibia, the naked Batraehia 
(Lissamphibia), probably originated even during the 
primary and secondary epochs, although fossil remains of 
them are first found in the tertiary epoch. They are 
distinguished from mailed Batraehia by possessing a naked 
smooth, and slimy skin, entirely without scales or coat of 
mail They probably developed either out of a branch of 
the Phractamphibia, or out of the same common root with 
them. The ontogeny of the three still living orders of naked 
Batraehia — the gilled Batraehia, tailed Batraehia, and frog 
Batraehia — distinctly repeats the historical course of de- 
velopment of the whole sub-class. The oldest forms are the 
gilled Batraehia (Sozobranchia), which retain throughout 
life the original primary form of naked Batraehia, and 
possess a long tail, together with water-breathing gills. 
They are most closely allied to the Dipneusta, from which. 


however, they differ externally by the absence of the coat 
of scales. Most gillcd Batrachia live in North America : 
among others of tlie class is the Axolotl, or Siredon, already 
mentioned. (Compare above, voL i. p. 241.) In Europe the 
order is only represented by one form, the celebrated " 01m" 
(Proteus angiiinus), which inhabits the grotto of Adelsberg 
and other caves in Carinthia, and which, from living in the 
dark, has acquired rudimentary eyes which can no longer see 
(voL i. p. 13). The order of Tailed Batrachia (Sozura) have 
developed out of the gilled Batrachia by the loss of external 
gills ; the order includes our black and yellow spotted land 
Salamander (Salamandra maculata), and pur nimble aquatic 
Salamandei-s (Tritons). Many of them — for instance, the 
celebrated giant Salamanders in Japan (Cryptobranchus 
Japonicus) — stUl retain the gill-slits, although the gills 
themselves have disappeared. All of them, however, retain 
the tail throughout life. Tritons occasionally — when 
forced to remain in water always — retain their gills, and 
thus remain at the same stage of development as gilled 
Batracliia. (Compare above, vol, i. p. 241.) The third order, 
the tailless or frog-like Batrachia (Anura), during their 
metamorphosis, not only lose their gills, with which in 
early life (as so-caUed tadpoles) they breathe in water, but 
also the tail with which they swim about. During their 
ontogeny, therefore, they pass through the course of 
development of the whole sub-class, they being at first 
Gilled Batrachia, then Tailed Batrachia, and finally Frog- 
like Batrachia. The inference from this is evidently, that 
Frog-like Batrachia developed at a later period out of 
Tailed Batrachia, as the latter had developed out of Gilled 
Batrachia which originally existed alone. 


In passing from the Amphibia to the next class of 
Vertebrata, namely, Reptiles, we observe a very considerable 
advance in the progress of organization. All the double- 
nostriled animals (Amphirrhina) up to this time considered, 
and more especially the two larger classes of Fish and 
Batrachia, agree in a number of important characteristics, 
which essentially distinguish them from the three remaining 
classes of Vertebrata — Reptiles, Birds, and Mammals. 
During tlie erabryological development of these latter, a 
peculiarly delicate covering, the first foetal membrane, or 
amnion, which commences at the navel, is formed round 
the embryo ; this membrane is filled with the amnion- 
water, and encloses the embryo or germ in the form of a 
bladder. On account of this very important and character- 
istic formation, we may comprise the three most highly 
developed classes of Vertebrata under the term AT^vnion- 
animals (Amniota). The four of double-nostriled 
animals Avhich we have just considered, in which the 
amnion is wanting (as is the case in all lower Vertebrate 
animals, single-nostriled and skull-less animals), may on 
the other hand be opposed to the others as amnion-less 
animals (Anamnia). 

The formation of the foetal membrane, or amnion, 
which distinguishes reptiles, birds, and mammals from all 
other Vertebrata, is evidently a very imjJortant process in 
their ontogeny, and in the phylogeny which corresponds 
with it. It coincides with a series of other processes, which 
essentially determine the higher development of Amnionate 
animals. The first of these imjDortant processes is the 
total loss of gills, for which reason the Amniota, under the 
name of Gill-less animals (Ebranchiata), were fomierly 


opposed to all other Vertebrate animals which breathed 
through gills (Branchiata). In all the Vertebrata already 
discussed, we found that they either always breathed 
through gills, or at least did so in early life, as in the 
case of Frogs and Salamanders. On the other hand, we 
never meet with a Reptile, Bird, or Mammal which at any 
period of its existence breathes through gills, and the gill- 
arches and openings which do exist in the embryos, are, 
during the course of the ontogeny, changed into entirely 
different structures, viz., into parts of the jaw-apparatus and 
the organ of hearing. (Compare above, vol. i. p. 307.) All 
Amnionate animals have a so-called cochlea in the organ of 
hearing, and a "round window" corresponding with it. These 
parts are wanting in the Amnion-less animals; moreover, their 
skull lies in a straight line with the axis of the vertebral 
column. In Amniotic animals the base of the skull appears 
bent in on the abdominal side, so that the head sinks upon 
the breast. (Plate III. Fig. 0, D, G, H.) The organs of tears 
at the side of the eye also first develop in the Amniota. 

The question now is. When did this important advance 
take place in the coxirse of the organic history of the earth ? 
When did the common ancestor of all Amniota develop out 
of a branch of the Non-amniota, to wit, out of the branch of 
the Amphibia ? 

To this question, the fossil remains of Vertebrata do 
not give us a very definite, but still they do give an 
approximate, answer. For with the exception of two 
lizard-like animals found in the Permian system (the 
Proterosaurus and Ehopalodon), all the fossil remains of 
Amniota, as yet known, belong to the secondary, tertiary, 
and quaternary epochs. With regard to the two Vertebrata 


just named, it is still doubtful whether they are genuine 
reptiles, or perhaps Amphibia of the salamander kind. 
Their skeleton alone is known to us, and even this not 
perfectly. Now as we know nothing of the characteristic 
features of their soft parts, it is quite possible that the 
Proterosaurus and Rhopalodon were non-amnionate animals 
more closely allied to Amphibia than to Reptiles ; possibly 
they belonged to the transition form between the two 
classes. But, on the other hand, as undoubted fossil remains 
of Amniota have been found as early as the Trias, it is 
probable that the main class of Amniota first developed in 
the Trias, that is, in the beginning of the Mesolithic epoch. 
As we have abeady seen, this very period is evidently one 
of the most important turning points in the organic history 
of the earth. The palaeolithic fern forests were then re- 
placed by the pine forests of the Trias period ; important 
transformations then took place in many of the classes of 
Invertebrata. Articulated marine lilies (Colocrina) (de- 
veloped out of the plated ones (Phatnocrina.) The Autechi- 
nidpe, or sea-urchins with only twenty rows of plates, took 
the place of the palasolithic Palechinidse, the sea-urchins 
with more than twenty rows of plates. The Cystidese, Blas- 
toidese, Trilobita, and other characteristic groups of Inverte- 
brata of the primary period became extinct. It is no 
wonder that transforming conditions of adaptation power- 
fully influenced the Vertebrate tribes also in the beginning 
of the Trias period, and caused the orij,ln of Amniotic 

If, however, the two Lizard and Salamander-like 
animals of the Permian system, the Proterosaurus and 
Ehopalodon, are considered genuine Keptiles, and conse- 


quently the most ancient Amniota, then the origin of this 
main class must necessarily have taken place in the 
preceding period, towards the end of the primary, namely, 
in the Permian period. However, all other remains of 
Reptiles, which were formerly believed to have been found 
in the Permian and the Coal system, or even in the Devonian 
system, have been proved to be either not remains of 
Reptiles at all, or to belong to a more recent date (for the 
most part to the Trias). (Compare Plate XIV.) 

The common hypothetical primary form of all Amniotic 
animals, which we may call Protaonnion, and which was 
possibly nearly related to the Proterosaurus, very probably 
stood upon the whole mid-way between salamanders and 
lizards, in regard to its bodily formation. Its descendants 
divided at an early period into two different lines, one of 
which became the common primary form of Reptiles and 
Birds, the other the primary form of Mammals. 

■Of all the three classes of Amniota, Reptiles (Reptilia, or 
Pholidota, also called Sauria in the widest sense), remain at 
the lowest stage of development, and differ least from their 
ancestors, the Amphibia. Hence they were formerly uni- 
versally included among them, although their whole 
organization is much more like that of Birds than Amphibia. 
There now exist only four orders of Reptiles, namely, — 
Lizards, Serpents, Crocodiles, and Tortoises. They, however 
foi-m but a poor remnant of the exceedingly various and 
higlily developed host of Reptiles which lived during the 
Mesolithic, or Secondary epoch, and predominated over all 
other Vertebrata. The immense development of Reptiles 
during tlie Secondary epoch is so characteristic that we 
could as well name it after those animals as after the 

tiaeclcel_ History of CreaHorii 

and Sofa-Classes, 



of the 







I Tviai gills, without Amnion. 

Fl. JW. 



Paired nostrilled or Amphirrhina 
with Amnion, without gills. 


Gymnosperms (p. 111). Twelve of the twenty-seven sub- 
orders, given on the aceompanjdng table, and four of the 
eight orders, belong exclusively to the secondary period. 
These mesolithic groups are marked by an asterisk. AU 
the orders, with the exception of Serpents, are found fossil 
even in the Jura and Trias periods. 

In the first order, that of Primary Reptiles, or Prim/i.ry 
Creepers (Tocosauria), we class the extinct Thecodontia of 
the Trias, together with those Eeptiles which we may look 
upon as the common primary form of the whole class. 
To the latter, which we may call Frimceval lieptiles 
(Proreptilia), the Proterosaurus of the Permian system 
very probably belongs. The seven remaining orders 
must be considered as diverging branches, which have 
developed in different directions out of that common 
primary form. The Thecodontia of the Trias, the only 
positively known fossil forms of Tocosauria, were Lizards 
which seem to have been like the still living monitor 
lizards (Monitor, Varanus). 

Of the four orders of reptiles now existing, and which, 
moreover, have alone represented the class since the 
beginning of the tertiary epoch, that of Lizards (Lacertilia) 
is probably most closely allied to the extinct Primary 
Reptiles, and especially through the monitors already 
named. The class of Serpents (Ophidia) developed out of a 
branch of the order of lizards, and this probably not until 
the beginning of the tertiary epoch. At least we at 
present only know of fossil remains of ser23ents from the 
tertiary strata. Crocodiles (Ci'oeodilia) existed much earlier ; 
the Teleosauria and Steneosauria belonging to the class are 
found fossil in large quantities even in the Jura ; but the 



Of the 8 Orders and 27 Sub-orders of Beptiles. 

(Those groups marked with * became extinct even during the Secondary Period.) 

of Iteptiles. 



Si/stematic Name 

of the 


A Generic Name 
an example. 

I. primarg 


, 2 

PrimfcBval rep- 

1. Proreptilia 

2. Thecodontia 

* (Proterosaurns ? 

* Palaeosaurna 

' 3 


3. Fissilingnes 


II. iLtjarts 




4. Crassilinguoa 




5. Brevilingnes 



Einged lizards 

6. Glj'ptodermata 


, 7. 


7. Vcrmilingues 


■ 8. 


8. Aglyphodonta 



Tree serpents 

9. Opisthoglj'pha 


III. Serpents . 



10. Proteroglypha 

11. Solenoglypha 



Worm serpents 

12. Opoterodonta 


lY. QLxata' ( ^^■ 


13. Teleosanria 

* Teleosaoms 

iilcs • l-l- 


14. Stcneosanria 

* Steneosatnus 

Crocodilia \ ^^■ 


15. Alligatores 



Sea tortoises 

16. Thalassita 


V. Eortoiscs 


Eiver tortoises 

17. Potamita 




Marsh tortoises 

18. Elodita 



Land tortoises 

19. Chersita 


VI. jrigins 

3aEptiIc3 - 
Pterosanria * 


Flying lizards 
Flying lizards 

20. Ehampho- 


21. Pterodactyli 

* Ehampho- 


* Pterodactylus 

VII. Sratjons 
Dinosauria * 


Giant dragons 

22. Harpagosauria 

23. Therosanria 

* Megalosanrua 

* Ignanodon 



24. Cynodontia 

* Dicynodon 

VIII. 33cakctl 



25. Cryptodontia 

* Udenodon 



Kangaroo rep- 

26. Hypsosauria 

* Compsognathns 

Anomodontia * 


Bird reptiles 

27. Tooornithes 

* (Tocomis) 


still living alligators are first met with in a fossU state 
in the chalk and tertiary strata. The most isolated of 
the four existing orders of reptiles consists of the re- 
markable group of Tortoises (Chelonia) ; fossils of these 
strange animals are first met with in the Jura. In some 
characteristics they are allied to Amphibia, in others, to 
Crocodiles, and by certain peculiarities even to Birds, so 
that their true position in the pedigree of Eeptiles is 
probably far down at the root. The extraordinary re- 
semblance of their embryos to Birds, manifested even at 
later stages of the ontogenesis, is exceedingly striking. 

The four extinct orders of Eeptiles show among one 
another, and, with the four existing orders just mentioned, 
such various and complicated relationships, that in the 
present state of our knowledge we are obliged to give up 
the attempt at establishing their pedigree. The most 
deviating and most curious forms are the Flying Reptiles 
(Pterosauria) ; flying lizards, in which the extremely elon- 
gated fifth finger of the hand served to support an enormous 
flying membrane. They probably flew about, in the 
secondary period, much in the same way as the bats of the 
present day. The smallest flying lizards were about the 
size of a sparrow ; the largest, however, with a breadth of 
wino" of more than sixteen feet, exceeded the largest of our 
living flying birds in stretch of wing (condor and albatross). 
Numerous fossil remains of them, of the long-tailed Rham- 
phorhynchia and of the short-tailed Pterodaetylfe are found 
in all the strata of the Jura and Chalk periods, but in these 

Not less remarkable and characteristic of the Mesolithic 
epoch was the group of Dragons (Dinosauria, or Pachypoda). 


These colossal reptiles, which attained a length of more than 
fifty feet, are the largest inhabitants of the land which have 
ever existed on our globe ; they lived exclusively in the 
secondary epoch. Most of their remains are found in the 
lower cretaceous system, more especially in the Wealden 
formations of England. The majoiity of them were fearful 
beasts of prey (the Megalosaurus from twenty to thirty, 
the Pclorosaurus from forty to fifty feet in length). The 
Iguanodon, however, and some others lived on vegetable 
food, and probably played a part in the forests of the chalk 
period similar to that of the unwieldy but smaller elepliants, 
hippopotami, and rhinoceroses of the present day. 

The Beaked Beptiles (Anomodontia), likewise also long 
since extinct, but of which very many remarkable remains 
are found in the Trias and Jura, were perhaps closely related 
to the Dragons. Their jaws, like those of most Flying 
Reptiles and Tortoises, had become changed into a beak, 
which either possessed only degenerated rudimentary teeth, 
or no teeth at alL In this order, if not in the preceding one, 
we must look for the primary parents of the bird class, which 
we may call Bird Reptiles (Tocornithes). Probably very 
closely related to them was the curious, kangaroo-like 
Compsognathus from the Jura, which in very important 
characteristics already shows an approximation to the 
structure of birds. 

The class of Birds (Aves), as ah-eady remarked, is so 
closely allied to Reptiles in internal structure and by 
embryonal development, that they undoubtedly originated 
out of a branch of this class. Even a glance at Plates II. 
and III. will show that the embryos of birds at a time 
\^'hen they already essentially difier from the embryos of 


Mammals, are still scarcely distinguishable from those of 
Tortoises and otlier Reptiles. The cleavage of the yolk is 
partial in the case of Birds and Reptiles, in Mammals it is 
total. The red blood-cells of the former possess a kernel, 
those of the latter do not. The hair of Mammals develops 
in closed follicles in the skin, but the feathers of birds and 
also the scales of reptiles develop in hillocks on the skin. 
The lower jaw of the latter is much more complicated than 
that of Mammals ; the latter do not possess the quadrate 
bone of the formej?. Whereas in Mammals (as in the case of 
Amphibia) the connection between the skull and the fii-st 
neck vertebra is formed by two knobbed joints, or condyles, 
in Birds and Reptiles these have become united into a single 
condyle. The two last classes may therefore justly be united 
into one group as Monocondylia, and contrasted to Mammals, 
or Dicondylia. 

The deviation of Birds from RejjtUes, in any case, first 
took place in the mesolithic epoch, and this moreover 
probably during the Trias. The oldest fossU remains of 
birds are found in the upper Jura (Archjeopteryx). But 
there existed, even in the Trias period, different Saurians 
(Anomodonta) which in many respects seem to form the 
transition from the Tocosauria to the primary ancestors of 
Birds, the hypothetical Tocornithes. Probably these Tocor- 
nithes were scarcely distinguishable from other beaked 
lizards in the system, and were closely related to the 
kangaroo-Uke Compsognathus from the Jura of Solenhofen. 
Huxley classes the latter with the Dinosauria, and believes 
them to be the nearest relations to the Toconiithes. 

The great majority of Birds — in spite of all the variety in 
the colouring of their beautiful feathery dross, and in the 


formation of their beaks and feet — are of an exceeedingly 
uniform organization, in much the same way as are the class 
of insects. The bird form has adapted itself on all sides to 
the external conditions of existence, without having thereby 
in any way essentially deviated from the strict hereditary 
type of its characteristic structure. There are oidy two 
small groups, the feather-tailed birds (Saururse) and those 
of the ostrich kind, which differ considerably from the 
usual type of bird, namely, from those with keel-shaped 
breasts (Carinat^), and hence the whole class may be divided 
into three sub-classes. 

The first sub-class, the Reptile-tailed, or Feather-tailed 
Birds (Saururse), are as yet known only through a single, 
and that an imperfect, fossil impression, which, however, in 
being the oldest and also a very peculiar fossil bird, is of 
great importance. This fossil is the Primasval Griffin, or 
Arch83opteryx lithographica, of which as yet only one speci- 
men has been found in the lithographic slate at Solenhofen. 
in the Upper Jura system of Bavaria. This remarkable 
bird seems on the whole to have been of the size and form 
of a large raven, especially as I'egards the legs, which are 
in a good state of preservation ; head and breast unfortun 
ately are wanting. The formation of the wings deviates 
somewhat from that of other birds, but that of the tail 
still more so. In all other birds the tail is very short and 
composed of but few short vertebrae ; the last of these have 
grown together into a thin, bony plate standing pei-pen- 
dicularly, upon which the rudder-feathers of the tail are 
attached in the form of a fan. The Archteopteiyx, however 
has a long tail like a lizard, composed of numerous (20) 
long thin vertebras, and on every vertebra are attached the 


strong rudder-feathers in twos, so that the whole tail 
appears regularly feathered. This same formation of the 
tail part of the vertebral column occurs transiently in the 
embryos of other birds, so that the tail of the Archteopteryx 
evidently represents the original form of bird-tail inherited 
from reptiles. Large numbers of similar birds with lizard- 
tails probably lived during the middle of the secondary 
period ; accident has as yet, however, only revealed this one 

The Fan4ailed, or Keel-hreccsted birds (CarinatiB), which 
form the second sub-class, comprise all living Birds of the 
present day, with the exception of those of the ostrich 
kind, or Eatitse. They probably developed out of Feather- 
tailed Birds during the first half of the secondary period, 
namely, in the Jura or chalk period, by the hinder tail 
vertebrae growing together, and by the tail becoming 
shortened. Only very few remains of them are known 
from the secondary period, and these moreover only out of 
the last section of it, namely, from the Chalk These remains 
belong to a swimming bird of the albatross species, and a 
wading bird like a snipe. All the other fossil remains of 
birds as yet known have been found in the tertiary 

The Bushy-tailed, or Ostrich-Woe Birds (Ratitse), also 
called Running Birds (Cursores), the third and last sub- 
class, is now represented only by a few living species, by 
the African ostrich with two toes, the American and 
Australian ostrich with three toes, by the Indian cassowary 
and the four-toed kiwi, or Apteryx, m New. Zealand. 
The extinct giant birds of Madagascar (iEpyornis) and the 
New Zealand Dinornis, which were much larger than the 


still living ostriches, also belong to this group. The Birds 
of the ostrich kind — by giving up the habit of flying, by 
the degeneration of the muscles for flying resulting from this, 
and of the breast bone which serves as their support, and 
by the corresponding stronger development of the hinder 
legs for running — have probably arisen out of a branch of 
the Keel-breasted birds. But possibly, as Huxley thinks, 
they may be the nearest relations of the Dinosauria and of 
the Reptiles akin to them, especially of the Compsognathus ; 
at all events, the common primary foim of all Birds must 
be looked for among the extinct Reptiles. 



IV. Mammals. 

The System of Mammals according to Linnasns and Blainville. — Three 
Sab-classea of Mammals (Ornithodelphia, Didelphia, Monodelphia). — 
Omithodelphia, or Monotrema, — Beaked Animals (Ornithostoma). — 
Didelphia, or Marsupials. — Herbivorous and CarniTorons Marsupials. — 
Monodelphia, or Placentalia (Placental Animals). — Meaning of the 
Placenta. — Tnft Placentalia.^Girdle Placentalia. — Disc Placentalia. — 
Non-deciduates, or Indeciduata. — Hoofed Animals. — Single and Double- 
hoofed Animals. — "Whales. — Toothless Animals. — Deciduates, or Animals 
with Decidua. — Semi.apes. — Gnawing Animals. — Pseudo-hoofed Ani- 
mals. — Inseotivora. — Beasts of Prey. — Bats. — Apes. 

There are only a few points in the classification of 
organisms upon wbich naturalists have always agreed. 
One of these few undisputed points is the privileged 
position of the class of Mammals at the head of the animal 
kingdom. The reason of this privilege consists partly 
in the special interest, also in the various uses and the 
many pleasures, which Mammals, more than all other 
animals, offer to man, and partly in the circumstance 
that man himself is a member of this class. For however 
differently in other respects man's position in nature and 
in the system of animals may have been regarded, yet no 
naturalist has ever doubted that man, at least from a purely 


morphological point of view, belongs to the class of Mam- 
mals. From this there directly follows the exceedingly 
important inference that man, by consanguinity also, is a 
member of this class of animals, and- has historically 
developed out of long since extinct forms of Mammals. 
This circumstance alone justifies us Jiere in turning our 
especial attention to the history and the pedigree of 
Mammals. Let us, therefore, for this purpose first examine 
the groups of this class of animals. 

Older naturalists, especially considering the formation of 
the jaw and feet, divided the class of Mammals into a 
series of from eight to sixteen orders. The lowest stage of 
the series was occupied by the whales, which seemed to differ 
most from man, who stands at the highest stage, by their 
fish-like form of body. Thus Linnceus distinguished the 
following eight orders : (1) Cetse (whales) ; (2) BeUuce 
(hippopotami and horses) ; (3) Pecora (ruminating animals) ; 

(4) Glires (gnawing animals and rhinoceroses) ; (5) Bestife 
(insectivora, marsupials, and various others) ; (6) Fera3 
(beasts of prey) ; (7) Bruta (tootliless animals and 
elephants) ; (8) Primates (bats, semi-apes, apes, and men). 
Cuvier's classification, which became the standard of most 
subsequent zoologists, did not rise much above that of 
Linnteus. Cuvier distinguished the following eight orders : 
(1) Cetacea (whales) ; (2) Euminantia (ruminating animals) ; 
(3) Pachyderma (hoofed animals, with the exclusion of 
ruminating animals) ; (4) Edentata (animals poor in teeth) ; 

(5) Rodentla (gnawing animals) ; (6) Carnassia (marsupials, 
beasts of prey, insectivora, and bats); (7) Quadrumana 
(semi-apes and aj)cs) ; (8) Bimana (man). 

The most important advance in the classification of 


Mammals was made as early as 1816 by the eminent 
anatomist Blainville, who has ah-eady been mentioned 
and who fii'st clearly recognised the three natural main 
groups or sub-classes of Mammals, and distinguished them 
aceordiEg to the formation of their generative organs as 
Ornitliodelphia, JDidelphia, and Monoclelphia. As this 
division is now justly considered by all scientific zoologists 
to be the best, on account of solid foundation on the history 
of development, let us here keep to it also. 

The first sub-class consists of the Cloacal Aninmls, or 
Breastless anivials, also called Forked animals (Monotrema, 
or Ornitliodelphia). This class is now represented only by 
two species of living mammals, both of which are confined to 
Australia and the neighbouriug island of Van Diemen's land 
namely, the well-known Water Duck-bill (Omithorhynchus 
paradoxus) with the beak of a bird, and the less known 
Beaked Mole (Echidna hystrix), resembHiig a hedgehog. 
Both of these curious animals, which are classed in the 
order of Beaked Animals (Ornithostoma), are evidently the 
last surviving remnants of an animal group formerly rich 
in forms, which alone represented the Mammalia in the 
secondary epoch, and out of which the second sub-class, the 
Didelphia, developed later, probably in the Jurassic period. 
Unfortunately, we as yet do not know with certainty of 
any fossil remains of this most ancient primary group 
of Mammals, which we wiU caU Primary Mammals (Pro- 
mammalia). Yet they possibly comprise the oldest of all 
the fossil Mammalia known, namely, the Microlestes antiquus, 
of which animals, however, we as yet only know some few 
small molar teeth. These have been found in the upper- 
most strata of the Trias, in the Keuper, first in Ger- 


many (at Degerlocli, near Stuttgart, in 1847), later also in 
England (at Frome), in 1858. Similar teeth have lately 
been found also in the North American Trias, and have been 
described as Dromatherium sylvestre. These remarkable 
teeth, from the characteristic form of which we can 
conclude that they belonged to an insectivorous mammal, 
are the only remains of mammals as yet found in the older 
secondary strata, namely, in the Trias. It is possible, 
however, that besides these many of the other mammalian 
teeth found in the Jura and Chalk systems, which are still 
generally ascribed to Marsupials, in reality belong to Cloacal 
Animals. This cannot be decided with certainty owing to 
the absence of the characteristic soft parts. In any case, 
numerous Monotrema, with well-developed teeth and cloaca, 
must have preceded the advent of Marsupial animals. 

The designation, " Cloacal animals" (Monotrema), has 
been given to the Ornithodelphia on account of the cloaca 
which distinguishes them from all other Mammals; but 
winch on the oiber hand makes them agree with Birds, 
Reptiles, and Amphibia, in fact, with the lower Vertebrata. 
The formation of the cloaca consists in the last portion of 
the intestinal canal receiving the mouth of the uroo-enital 
apparatus, that is, the united urinary and genital organs, 
whereas in all other Mammals (Didelphia as well Mono- 
delphia) these organs have an opening distinct from that 
of the rectum. However, in these latter also the cloaca 
formation exists during the first period of their embryonal 
life, and the separation of the two openings takes place only 
at a later date (in man about the twelfth week of develop- 
ment). The Cloacal animals have also been called " Forked 
animals" because the coUar-bones, by means of the breast 


bone, have become united into one piece, similar to the well- 
known fork-bone, or meiTy-thought, in birds. In all other 
Mammals the two collar-bones remain separated in front 
and do not fuse with the breast bone. Moreover, the 
coracoid bones are much more strongly developed in the 
Cloacal animals than in the other Mammalia, and are con- 
nected with the breast bone. 

In many other characteristics also — especially in the 
formation of their internal genital organs, their auricular 
labyrinth, and their brain — Beaked animals are more closely 
allied to the other Vertebrata than to Mammals, so that some 
naturalists have been inclined to separate them from the 
latter as a special class. However, like all other Mammals, 
they bring forth living J'oung ones, which for a time are 
nourished with milk from the mother. But whereas in all 
other Mammals the milk issues through nipples, or teats, 
from the mammary glands, teats are completely wanting 
in beaked animals, and the milk comes simply out of a flat, 
sieve-like, perforated patch of the skin. Hence they may 
also be called Breastless or Teatless aninnals (Amasta). 

The curious formation of the beak in the two still living 
Beaked animals, which is connected T^^ith the suppression 
of the teeth, must evidently not be looked upon as an 
essential feature of the whole sub-class of Cloacal animals, 
but as an accidental character of adaptation distinguishing 
the last remnant of the class as much from the extinct' main 
group, as the formation of a similar toothless snout dis- 
tinguishes many toothless animals (for instance, the ant- 
eater) from the other placental animals. The unknown, 
extinct Primary Mammals, or Promammalia — which lived 
during- the Trias period> and of which the two stiU living 


orders of Beaked animals represent but a single degenerated 
branch developed on one side — probably possessed a very 
highly developed jaw like the marsupial animals, which 
developed from them. 

Marsupial, or Pouched Animals (Didelphia, or Marsu- 
pialia), the second of the three sub-classes of Mammals, 
form in every respect — both as regards their anatomy and 
embryology, as well as their genealogy and history — the 
transition between the other sub-classes — the Cloacal and 
Placental Animals. Numerous representatives of this group 
still exist, especially the well-known kangaroos, pouched 
rats, and pouched dogs ; but on the whole this sub-class, 
like the preceding one, is evidently approaching its complete 
extinction, and the living members of the class are the last 
surviving remnants of a large group rich in forms, which 
represented the Mammalia during the more recent secondary 
and the earlier tertiary periods. The Marsupial Animals 
probably developed towards the middle of the Mesolithic 
epoch (during the Jura) out of a branch of the Cloacal 
Animals, and in the beginning of the Tertiary epoch again, 
the group of Placental Animals arose out of the Marsupials, 
and the latter then succumbed to the former in the struggle 
for life. All the fossil remains of Mammals known to us from 
the Secondary epoch, belong either exclusively to Marsupials, 
or partly perhaps to Cloacal animals. At that time Marsu- 
pials seem to have been distributed over the whole earth ; 
even in Europe (France and England), well-preserved fossil 
remains of them have been found. On the other hand, the 
last off-shoots of the sub-class now living are confined to a 
very nan-ow tract of distribution, namely, to Australia, the 
Australasian, and a small part of the Asiatic, Archipelago. 


There are also a few species still living in America, but at 
the present day not a single marsupial animal lives on the 
continent of Asia, Africa, or Europe. 

The name of pouched animals is given to the class on 
account of the purse-shaped pouch (marsupium) existing 
in most instances on the abdominal side of the female 
animals, in which the mother carries about her young 
for a considerable time after their birth. This pouch is 
supported by two characteristic marsupial bones, also 
existing in Cloacal animals, but not in Placental animals. 
The young Marsupial animal is bom in a much more 
imperfect form than the young Placental animal, and only 
attains the same degree of development which the latter 
possesses directly at its birth, after it has developed in the 
pouch for some time. In the case of the giant kangaroo, 
which attains the height of a man, the newly born yoxm<T 
one, which has been carried in the maternal womb not 
much longer than five weeks, is not more than an inch 
in length, and only attains its essential development 
subsequently, in the pouch of the mother, where it remains 
about nine months attached to the nipple of the mammary 

The different divisions generally distinguished as families 
in the sub-class of Marsupial animals, deserve in reahty 
the rank of independent orders, for they differ from one 
another in manifold differentiations of the jaw and limbs, in 
much the same manner, although not so shar2oly, as the 
various orders of Placental animals. In part they perfectly 
agree with the latter. It is evident that adaptation to 
similar conditions of life has effected entirely coincident or 
analoojous transformations of the oi'iginal fundamental form 


in the two sub-classes of Marsupials. According to this, 
about eight orders of Marsupial animals may be dis- 
tinguished, the one half of the main group or legion of 
which are herbivorous, the other half carnivorous. The 
oldest fossil remains of the two legions (if the previously 
mentioned Microlestes and the Dromatherium are not 
included) occur in the Jurassic strata, namely, in the 
slates of Stonesfield, near Oxford. The slates belong to the 
Bath, or the Lower Oolite formation — strata which lie directly 
above the Lias, the oldest Jura formation. (Compare p. 15). 
It is true that the remains of Marsupials found in the slates 
of Stoneslield, as well as those Avhich were found later in 
the Purbeck strata, consist only of lower jaws. (Compare 
p. 29.) But fortunately the lower jaw is just one of the most 
characteristic parts of the skeleton of Marsupials. For it is 
distinguished by a hook-sliaped process of the lower comer 
of the jaw turning downwards and backwards, which 
neither occurs in Placental nor in the (still living) Cloacal 
animals, and from the existence of this process on the lower 
jaws from Stonesfield, we may infer that they belonged to 

Of Herhivorous marsropials (Botanophaga), only two 
fossils are as yet known from the Jura, namely, the Stereo- 
gnathus ooliticus,from the slates of Stonesfield (Lower Oolite), 
and the Plagiaulax Becklesii, from the middle Purbeck strata 
(Upper Oolite). But in Australia there are gigantic fossil 
remains of extinct herbivorous Marsupials from the diluvial 
period (Diprotodon and Nototherium) which were far larger 
than the largest of tlie still living Marsupials. The Diproto- 
don Australis, whose skull alone is three feet long, exceeded 
even the river-horse, or Hippopotanms, in size and upon the 




I, First Sui-class of Mammalia, : 

ForJced or Cloacal Animah (Ilonotrema, or Ornithodelpliia). 

Mamtnals -with Cloaca, without Placenja, with Marsupial Bones. 

33tiinatO fttantmals ( Unknown extinct Mammalia from the j (Mi' 
■r, " , . 1 'i'rias rcriod { (Dri 

Promammalia \ 

crolestos ?) 

33EaIvtii animals 

1. Aquatic beaked 


2. Terrestrial 

beaked animals 

1. Ornifliorliyu- 

Z. Echidnida 

(1. Ornithorhyncliua 
i paradoxus 

1 2. Echidua hystrix 

II. Second Suh-class of Mammalia : 

Pouched or Marsuxiial Animals (Marsupialia, or Didelphia). 

Maunnals without Cloaca, without Placenta, with Marsupial Bones. 



Systematic Name 

Families of the 



the Orders. 


1 1. Hoofed 
Marsupial auimals 

1. Barjpoda ( 1. Stereoguatbida 
■j 2. Nototherida 
( 3. Diprotodontia 



2. Kangaroo 

Miirsupirtl anim;ll3 

(Leaping pouched 


2. uracropoda 

4. Plap^iaulacida 

■ 5. JEalmaturida 

6. DeudiolagiUa 


3. Iioot-catiii^ 

ftlarsupial animals 

(Gnawing- penciled 


Z. Kliizophaga ( 

i 7. riiascoloniyida 


4. Fruit eating- 
Marsupial aniniiila 
(Climbing pouchct 
\ auimals) 

4, Carpoijliaga 

j 8. Thascolarctida 
{ 9. Plialaugistida 
ho. I'etaurida 







5. Insectivorous 

Marsupial animals 

(rriniitval pouched 


6. Marsupial animals 

poor in teeth 

(Pouched animals 

with trunks) 

7. Eapncions marsu- 

pial animals 

(Uapacious pouched 


8. Ape-footed 

^Taraupial animals 

(Pouched animals 

witli hands) 

5. Cantharophaga r^^ Thylacotherida 
1 12. Spalacotherida 
\ 13. I^tyrmecobida 
( 14. rerauiellda 

6. Edentula 

7. Creophaga 

8. FedimaDa 

15. TarsipGdina 

IG. DasTurida 
17- Thylacinida 
18. Thylacoleonida 

10. Chironoctida 
2!). Pidclphyida 




III. Third Sitb-class of Mammalia : 
Placentalia, or Alonodelphia, (Placental Animals). 

Mammals witliont Cloaca, with Placenta, without Marsupial Bones. 

. Legions of 
Flacental Animals. 

Orders 0/ 

riacmtat Animals. 

Suh-orders of 
Placental Animals. 

Si/stemutic Kain£ 


the Sub-orders. 

Ill, 1. Indecidua. Placental Animals witliout Decidua. 

jlloofrtt Animals 




jjoov in Uct}) 

I. Siiijrle-lioofud f 1. 

Ferissodact'/la 1 2, 

11. DoublG-luMied J 3, 

Arllodaciyla \ i. 

I III. Herbivorous 
IV. Carnivorous 

i V.Di;;-ging Animals ( 8. 
Ejjodientkt, \ 0. 


5. Sea cows 

VT. Rlotlis 



Giant Slolhs 
Dwarf SIoLhs 

1. TapirODiorplia 

2. SoUduii|ai.Ua 

3. Cliooromorpha 
1 liuQiinautlih 

6. Sirenia 

6. Autoceta 

7. Zeugloceta 

8. Vciinilinguia 

9. Ciujiuhita 

10. Gravigrada 

11. Taidiiirada 

III, 2. Deciduata. Placental Animals with Docidua. 

piacttttal ^m= 

ma Is. 

f VII. Rapacious 

VIII. Falsp.-hoofcd 

JX. Semi-apes 




X. Gnawing Ani- 

mals i 

Jiodcntia I 

XI. Insect-eating- r 
Animals ? 

Jnsccth'ora { 

XII. Flying Animals f 

Chiroptera \ 

XIII. Apes ( 

SiJiiioi "J 

Ilapflcious laud 

Eapacious sea 


Fingered ani- 
Flying lemur 
Short -footed 
Squirrel species 
Mouse species 
rorcupine spe- 
Hare species 
\^'itl^ a Coccum 
Without a Coe- 

riying foses: 

Clawed apes 
Flat -nosed 

12. Carnivora 

13. Pinnipedia 

14. Lamnunpa 

15. Toxodontia 
10. Gonyog-natha 

17. Froboscidea 

18. Leptodactyla 

10. Ptenoplcura 
'20. Macrotarsi 

21. Brachytarsi 

22. Sciuromorpha 
Zi. Myomoiplui 

24. HystricLomorpha 

25. La^omorplia 
20. Menotyphla 

27. Lipotyphla 

28. rterocynes 

29. Kycterides 

30. Arctopitheci 

31. Platyrrhinae 

32. CatarrhiiiEB 





Eock Conies 

ITan-ow nosed 

Psendo -hoofed 


©nafaing 9nitnals 

Fingered animals 




I Marino animals of prey 
Flying foxes ■^'™«P«'i^ 
JTiuinn; SnimKls 

Land animals of prey 

atnimals of ^rc2 

In?eot caters 

Sea cows 




I Poor in teeth 

I Edentata, 

j^nnfct) animals 




JDccilinaus Snimals 


|3kccntal Animals 

Herbivorons marsnpials 
Marsupialia iotcmojphaga 

Carnivorons nmrsnpia,T3 
Marsupialia zoophaga 

Beaked animals 


Primary mammals 


ffiloacal aimmals 



whole resembled it in the unwieldy and clumsy form of 
body. This extinct group, which probably coiTesponded with 
the gigantic placental hoofed animals of the present day — 
the hippopotami and rhinoceroses — may be called Hoofed 
Marsupials (Barypoda). Closely allied to them is the order 
of kangaroos, or Leaping Marsupials (Macropoda), which 
all have seen in zoological gardens. In their shortened 
fore legs, their very lengthened hind legs, and very strong 
tail, which serves as a jumping pole, they correspond with 
the leaping mice in the class of Rodents. Their jaw, how- 
ever, resembles that of horses, and their complex stomach 
that of Ruminants. A third order of Herbivorous Marsupials 
corresponds in its jaws to Rodents, and in its subterranean 
mode of life, especially, to digging mice. Hence they may 
be termed Rodent Marsupials, or root-eating pouched animals 
(Rhizophaga). They are now represented only by the 
Australian wombat (Phascolomys). A fourth and last order 
of Herbivorous Marsupials is formed by the climbing or 
Fruit-eatiag Marsupials (Carpophaga), whose mode of life 
and structure resembles partly that of sq^uirrels, partly 
that of apes (Phalangista, Phascolarctus). 

The second legion of Marsupials, the Carnivorous Mar- 
supials (Zoophaga), is likewise divided into four main 
groups or orders. The most ancient of these is that of the 
primaeval, or Insectivorous Marsupials (Cantharophaga). It 
probably includes the primary forms of the whole legion, 
and possibly also those of the whole sub-class. At least, all 
the lower jaws from Stonesfield (with the exception of the 
Stereognathus) belong to Insectivorous Marsupials, and the 
still living Myi'mccobius is their nearest relative. But some 
of those oolitic Prima3val Marsupials possessed a larger 


numLer of teeth than all the other known mammals, for 
each half of the lower jaw of the Thylacotherium contained 
sixteen teeth (three incisors, one canine tooth, six pseudo, 
and six genuine molars). If the upper jaw, which is 
unknown, had as many teeth, then the Thylacotherium had 
no less than sixty-four teeth, just double the number 
possessed by man. The Primeeval Marsupials correspond, 
on the whole, with the Insectivora among Placental animals, 
"which order includes hedgehogs, moles, and shrew-mice. A 
second order, which has probably developed out of a 
branch of the last, consists of the Snouted, or Toothless 
Marsupials (Edentula), which resemble the Toothless animals, 
or Edentata, among the Placental animals by their tube- 
shaped snout, their degenerated jaws, and their correspond- 
ing mode of life. On the other hand, the mode of life and 
formation of the jaws of 'Eapacious marsupials (Creophaga) 
correspond with those of the genuine Beasts of Prey, or 
Carnivora, among Placental animals. This order includes the 
pouched marten (Dasyurus) and the pouched wolf (Thyla- 
cinus) in Australia. Although the latter attains to the size 
of a wolf, it is but a dwarf in comparison with the extinct 
Australian pouched lions (Thylacolco) which were at least as 
large as a lion, and possessed huge canine teeth more than 
two inches in length. Finally, the eighth and last order is 
formed by the marsupials with hands, or the Ape-footed 
Pouched animals (Pedimana), which live both in Australia and 
America. They are frequently kept in zoological gardens, 
especially the different species of the genus Didelphys, and 
are known by the name of pouched rats, bush rats, or 
opossums. The thumb on their hinder feet is opposable to 
the four other toes, as in a hand, and by this they are 


directly allied to the Semi-apes, or Pi'osimia, among Placental 
animals. It is possible that these latter are really next 
akin to the marsupials with hands, and that they have 
developed out of their long since extinct ancestors. 

It is very difficult to discover the genealogy of Marsupials, 
and this more especially because we are but very imperfectly 
acquainted with the whole sub-class ; and tlie Marsupials of 
the present day are evidently only the last remnants of a 
group that was at one time rich in forms. It is possible 
that Marsupials with hands, those with snouts, as weU as 
rapacious Marsupials, developed as three diverging branches 
out of the common primary group of Primaival Marsupials. 
In a similar manner, on the other hand, the rodent, leaping, 
and hoofed Marsupials have perhaps arisen as three diverging 
branches out of the common herbivorous primary group, 
that is, out of the Climbing Marsupials. Climbing and 
Primasval Marsupials might, however, be two diverging 
branches of the common primary forms of all Marsupials, 
that is, of the Frionary Marsupials (Prodidelphia), which 
originated during the older secondary period out of Cloacal 

The third and last sub-class of mammals comprises the 
Placental animals, or Flacentals (Monodelphia, or Placen- 
talia). It is by far the most important, comprehensive, and 
most perfect of the three sub-classes ; for the class includes 
all the known mammalia, with the exception of Marsupials 
and Beaked animals. Man also belongs to this sub-class, 
and has developed out of its lower members. 

Placental animals, as then' name indicates, are distin- 
guished from all other mammals, more especially by the 
formation of a so called placeoita. This is a very peculiar 


and remarkable organ, whicti plays an ekceedingly im- 
portant part in nourishing the young one developing in the 
maternal body. The placenta (also called after-birth) is a 
soft, spongy, red body, which differs very much in form and 
size, but which consists for the most part of an intricate 
network of veins and blood vessels. Its importance lies in 
the exchange of substance between the nutritive blood of 
the maternal womb, or uterus, and the body of the germ, 
or embryo. (See vol i. p. 298). This very important organ 
is developed neither in marsupials nor in beaked animals. 
But placental animals are also distinguished from these two 
sub-classes by many other peculiarities, thus more especially 
by the absence of marsupial bones, by the higher develop- 
ment of the internal sexual organs, and by the more perfect 
development of the brain, especially of the so-caUed callous 
body or beam (corpus callosum), which, as the intermediate 
commissure, or transverse bridge, connects the two hemi- 
spheres of the large brain with each other. Placental ani- 
mals also do not possess the peculiar hooked process of the 
lower jaw which characterizes Marsupials. The following 
classification (p. 246) of the most important characteristics 
of the three sub-classes will best explain how Marsupials, in 
these anatomical respects, stand midway between Cloacal 
and Placental animals. 

Placental animals are more variously differentiated and 
perfected, and this, moreover, in a far higher degree, than 
Marsupials, and they have, on this account, long siace been 
arranged into a number of orders, differing principally in 
the formation of the jaws and feet. But what is even of 
more importance than these, is the different development of 
the placenta, and the manner of its connection with the 



maternal uterus. For in the three lower orders of Placental 
animals, in Hoofed animals, Whales, and Toothless animals, 
the peculiar spongy membrane, which is called the deciduous 
viembrane, or deoidua, and which connects the maternal and 
the foetal portions of the placenta, does not become de- 
veloped. This takes place exclusively in the seven higher 
orders of Placental animals, and Ave may, therefore, according 

Three Snii-Classes 

Cloaca/' Animals 


Pouched Animals 
Mars u ITALIA 

Placental Animals 








1. Cloaca formation 




2. Nipples of the pec- 




toral glands, or milk 


3. Fore collar bones, 


Not nnited 

Not united 

or clavicles, grown to- 

gether in the middle. 

"with the breast bone, 

and forming a forked 


4. Marsupial bones 




5. Corpus callosuni of 



Strongly developed 

the brain 



G. Placenta 




to Huxley, class them in the main group of Deciduata, or 
animals with decidua. They are contrasted with the three 
first-mentioned legions of indeciduous animals, or Inde- 

But in the various orders of Placental animals the placenta 
difiers not only in important internal differences of struc- 
ture, which are connected with the absence or the presence 


of a deeidua, but also in the external form of the placenta 
itself. In the Indeciduata it consists, in most cases, of 
numerous, single, scattered bunches or tufts of vessels, and 
hence this group may be called tufted ■placental animals, 
(Villiplacentalia). In the Deciduata, however, the single 
tufts of vessels are united into a cake, which appears in two 
different forms. In the one case it surrounds the embryo in 
the form of a closed band or ring, so that only the two poles 
of the oval egg bladder are free of tufts ; this is the case in 
animals of prey (Carnaria)'and the pseudo-hoofed animals 
(Chelophora), which may consequently be comprised as 
girdled-placental animals (Zonoplacentalia). In the other 
Deciduata, to which man also belongs, the placenta is a 
simple round disc, and we therefore call them disc-placen- 
tals (Discoplacentalia). This group includes the five orders 
of Semi-apes, Gnawing animals, Insectivora, Bats, and Apes, 
from the latter of which, hi the zoological system, man 
cannot be separated 

It may be considered as quite certain, from reasons based 
upon their comparative anatomy and their history of de- 
velopment, that Placental animals first developed out of 
Marsupials, and that this very important development — the 
first origin of the placenta — probably took place in the 
beginning of the tertiary epoch, during the eocene period. 
But one of the most difficult questions in the genealogy of 
animals is the important consideration whether all Placental 
animals have arisen out of one or out of several distinct 
branches of Marsupials ; in other words, whether the origin 
of the placenta occurred but once, or several times. 

When, in my General Morphology, I for the first time 
endeavoured to establish the pedigree of Mammals, I here. 


as in most cases, preferred the monophyletle, or one-rooted, 
to the polyphyletic, or many-rooted, hypothesis of descent. 
I assumed that all Placental animals were derived from a 
single form of Marsupial animal, which, for the first time, 
began to form a placenta. In this ease the Villiplacentals, 
Zonoplacentals, and Discoplacentals would perhaps have to 
be considered as three diverging branches of the common 
primary form of Placentals, or it might also be conceived that 
the two latter, the Deciduata, had developed only at a later 
period out of the Indeciduata, which on their part had 
arisen directly out of the Marsupials. However, there are 
also important reasons for the alternative; namely, that 
several groups of Placentals, differing from the beginning, 
arose out of several distinct grouj)s of Marsupials, so that 
the placenta itself was formed several times independently. 
This opinion is maintained by Huxley, the most eminent 
English zoologist, and by many others. In this case the 
Indeciduata and the Deciduata would perhaps have to be 
considered as two completely distinct groups ; then the 
order of Hoofed animals, as tlie primary group of the 
Indeciduata, might be supposed to have originated out 
of the Marsupial hoofed animals (Barypoda). Among the 
Deciduata, on the other hand, the order of Semi-apes, as the 
common primary form of the other orders, might possibly 
have arisen out of Handed Marsupials (Pedimana). But it 
is also conceivable that the Deciduata themselves have arisen 
out of several different orders of Marsupials, Animals of Prey 
out of Rapacious Marsupials, Gnawing animals out of Gnaw- 
ing Marsupials, Semi-apes out of Handed Marsupials, etc. 
As we do not at present possess sufficient empiric material 
to solve this most difficult question, we must leave it and 


turn our attention to the history of the different orders 
of Placental animals, whose pedigree can often be very 
accurately established in detail. 

We must, as already remarked, consider the order of 
Hoofed animals (Ungulata) as the primary group of the 
Indeciduata, or Tuft-placentals ; the two other orders. 
Whales and Toothless animals, developed out of them, as 
two diverging groups, probably only at a later period, by 
adaptation to very different modes of life. But it is also 
possible that the animals poor in teeth (Edentata) may be 
of quite a different origin. 

Hoofed animals are in many respects among the most 
important and the most interesting Mammals. They dis- 
tinctly show that a true understanding of the natural 
relationship of animals can never be revealed to us merely 
by the study of living forms, but in all cases only by an 
equal consideration of their extinct and fossil blood-relations 
and ancestors. If, as is usually done, only the living Hoofed 
animals are taken into consideration, it seems quite natural 
to divide them into three entirely distinct orders, namely: 

(1) Horses, or Single-hoofed animals (SolidunguIa,or Equina); 

(2) Ruminating animals, or Douhle-hoofed (Bisulca, or Rumi- 
nantia) ; and (3) Thick-skinned, or Many-hoofed (Multungula, 
or Pachyderma). But as soon as the extinct Hoofed animals 
of the tertiary period are taken into consideration — of which 
animals we possess very numerous and important remains 
— it is seen that this division, but more especially the 
limitation of the Thick-skinned animals, is completely arti- 
ficial, and that these three groups are merely top branches 
lopped from the pedigree of Hoofed animals, which are most 
closely connected by extinct intermediate forms. The one 


half of the Thick-skinned animals — rhinoceroses, tapirs, and 
palasotheria — manifest the closest relationships to horses, 
and have like them odd-toed feet ; whereas the other 
half of the Thick-skimied animals — pigs, hij^popotami, and 
anoplotheiia — on account of their double-toed feet are much 
more closely allied to ruminating animals than to the 
former. Hence we must, in the first place, among Hoofed 
animals distinguish the two orders of Paired-hoofs and Odd- 
hoofs, as two natural groups, which developed as diverging 
branches out of the old tertiary primary group of Primary 
Hoofed animals, or Prochela. 

The order of Odd-hoofed animals (Perissodactyla) com- 
prises those Ungulata in which the middle (or third) toe of 
the foot is much moi-e strongly developed than the others, 
so that it forms the actual centre of the hoof This order 
includes the very ancient, common, primary gi'oup of all 
Hoofed animals, that is, the Primary-hoofed animals (Pro- 
chela), which are found in a fossil state in the oldest Eocene 
strata (Lophiodon, Coryphodon, Pliolophus). Directly alHed 
to this gTOup is that branch which is the actual primary 
form of the Odd-hoofed animals, namely, the Palceotheria, 
fossils of which occur in the upper Eocene and lower 
Pliocene. Out of the Palasotheria, at a later period, the 
rhinoceroses (Nasicornia) and rhinoceros-horses (Elasmo- 
therida) on the one hand, and the tapirs, lama-tapirs, and 
primceval horses, on the other, developed as two divergino- 
branches. The long since extinct primjEval horses, or 
Anchitheria, formed the transition from the Palaootheria 
and tapirs to the Miocene horses, or hipparions, which 
are closely allied to the genuine living horses. 

The second main group of Hoofed animals, the order of 


Pair-Jioofed aniTuals (Artiodactyla), comprises those hoofed 
animals in which the middle (third) and fourth toe of the 
foot are almost equally developed, so that the space between 
the two forms the central line of the entire foot. The order 
is divided into two sub-orders — the Pig-shaj)ed and the Cud- 
chewing, or Ruminating. The Pig-shaped (Choeromorpha) 
comprise in the first place the other branch of Primary- 
Hoofed-animals, the Anoplotheria, which we consider as the 
common primary form of all Pair-hoofed animals, or Artio- 
dactyla (Dichobune, etc.) Out of the Anioplotheria arose, r.s 
two diverging branches, the primssval swine, or Anthraco- 
theria, on the one hand, forming the transition to swine and 
river-horses, and the Xiphodonta on the other hand, forming 
the transition to Ruminating animals. The oldest Rumin- 
ating animals (Ruminantia) are the Primseval Stags, or Dre- 
motheria, out of which, possibly, the stag-shaped (Elaphia), 
the hoUow-horned (Cavicornia), and camels (Tylopoda), have 
developed as three diverging branches. Yet these latter are, 
in many respects, more allied to the Odd-hoofs than to the 
genuine Pair-hoofs. The accompanying systematic survey 
on p. 252, will show how the numerous families of Hoofed 
animals are grouped, in correspondence with this genea- 
logical ■ hypothesis. 

It is probable that the remarkable legion of Whales 
(Cetacea) originated out of Hoofed animals, which accustomed 
themselves exclusively to an aquatic life, and thereby became 
transformed into the shape of fish. Although these animals 
seem externally very like many genuine Fish, yet they are, 
as even Aristotle perceived, genuine Mammals. By their 
whole internal structure — in so far as it. has not become 
changed by adaptation to an aquatic life — they, of all known 




Of the Sections and Families of Hoofed Animals, or Ungulala. 

( Tliose families that are extinct are marked with an asterisk.) 



Hoofed Animals. 



Boofed Animals. 

Systematic Nama 


the Families. 





' I. Primary Hoofed 




II. Tapir.sliaped 

III. Single-hoofs 

TV. Pjg-sliaped , 

A. Stag- 



ating \ 



B. Hollow- 






*, Tylojjudcb \ 27. 



Lama- tapirs 








KiTcr horses 


15. PrimBeval 


16. Pseado 
musk deer 

17. Mnsk deer 

18. Deer 

19. Primeval 


20. Giraffes 

21. Primoeval 

22. Gazelles 

[23. Goats 
24. Sheep 
( 25. Oxen 


1. Lophiodontia * 

2. Pliolophida* 

3. Palceotherida * 

4. Macrauohenida*' 

5. Tapirida 

6. Nasicornia 

7. Elasmothe- 

rida * 

8. Anchitherida * 

9. Equina 

10. Anoplothe- 

rida * 

11. Antliracothe- 

rida * 

12. Setigera 

13. Obesa 

14. Xiphodontia * 

15. Dreiaotherida 

16. Tragulida 

17. MosohiJa 

18. Cervina 

19. Sivatherida * 

20. Devexa 

21. Autilocaj5rina* 

22 Antilopina 

23. Caprina 

24. Ovina 

25. Eovina 

2G. Auchenida 
27. Camelida 








'Musk deer 



■' and Lamas Intermediate horses 

Hollow -horned 

Deer-shaped Tylopoda Mippariones 

Prima3val deer 

Primaeval horses 




1 Eivor-horsea 

l^umtiMting animals 



PrimasTal pigs 




Primaeval ruminants ' 

JPttTtttttg PliTsfjDDfa 

Jprimatg ®1i1)=Ijiib£3 



{Lophiodontia and PUolophida) 

(Hoofed marsupials ? Barypoda f ) 


Mammals, are most closely allied to Hoofed animals, and 
more especially agree with them in the absence of the 
decidua and in the tufted placenta. Even at the present day 
the river-horse (Hippopotamus) constitutes a kind of transi- 
tion form to the Sea Cows (Sirenia), and from this it seems 
most probable that the extinct primary forms of the Cetacea 
are most closely allied to the Sea Cows of the present day, 
and that they developed out of Pair-hoofed animals, which 
were related to the hippopotamus. Out of the order of 
Herhivorous whales (Phycoceta) — to which the sea cows be- 
long, and which accordingly, very probably, contain the 
primary forms of the legion — the other order of Carnivorous 
whales (Sarcoceta) appears to have developed at a later 
period- But Huxley thinks that these latter were of quite a 
different origin, and that they arose out of the Carnaria 
through the Seals. Among the Sarcoceta, the extinct gigantic 
Zeuglodonta (Zeugloceta) — whose fossil skeletons some time 
ago excited great interest, it being thought that they were 
"sea serpents" — arc probably only a peculiarly developed 
lateral branch of genuine whales (Autoceta), which com- 
prise, besides the colossal whalebone whales, the cachalot or 
spermaceti whales, dolphins, narwhals, porpoises, etc. 

The thu-d legion of the Indeciduata, or Sparsi-placentalia, 
comprises the strange group of the animals poor in teeth 
(Edentata) ; it is composed of the two orders of burrowers 
and sloths. The order of Burroivers (EfFodientia) consists 
of the two sub-orders of ant eaters (Vermilinguia), to 
which the scaled animals also belong, and the girdle 
animals (Cingulata), which were formerly represented by 
the gigantic GlyptodoiLs. The order of Sloths (Tardigrada) 
consists of the two sub-orders of the small, stiU living 


dwarf slotlx& fBradypoda), and of the extinct unwieldy 
giant sloths (Gravigrada). The enormous fossil remains 
of these colossal herbivora suggest that the "whole legion 
is becoming extinct, and that the Edentata of the present 
day are but a poor remnant of the mighty order of the 
diluvial period. The close relations between the still 
living South American Edentata and the extinct gigantic 
forms which are found beside the latter on the same part of 
the globe, made such an impression upon Darwin on his 
first visit to South America, that they even then suggested 
to him the fundamental idea of the Theory of Descent. (See 
above, vol. i. p. 13-i). But it is precisely the genealogy of this 
legion which is most difficult. The Edentata are perhaps 
nothing but a peculiarly developed lateral branch of the 
Ungulata ; but it may also be that their root lies in quite 
another direction. 

We now leave the first main group of Placental animals, 
the Indeciduata, and turn to the second main group, 
namely, the Deciduata, or animals with decidua, which are 
distinguished from the former by possessing a deciduous 
membrane, or decidua, during their embryonal life. We 
here meet with a very remarkable small group of animals, 
for the most part extinct, and which probably were the 
old tertiary (or eocene) ancestors of man. These are the 
Semi-apes, or Lemurs (Prosimije) ; these curious animals 
are probably the but little changed descendants of the 
primseval group of Placentalia which we have to consider 
as the common primary form of all Deciduata. They have 
hitherto been classed together in the same order with Apes 
-which Blumenbach called Quadrumana (four-handed). How- 
ever, I regard them as entirely distinct from these, not 


merely because they differ from all ApeS, mucli more than 
do the most different Apes from one another, but also because 
they comprise most interesting transitional forms leading 
to the other orders of Deciduata. I conclude from this that 
the few still living Semi-apes, which moreover differ very 
much among one another, are the last surviving remnants 
of a primary group now almost extinct, but which was 
at one time rich in forms, and out of which all the other 
Deciduata (possibly with the single exception of Beasts of 
Prey, and Pseudo-hoofed animals) have developed as diverg- 
ing branches. The old primary group of Semi-apes has 
probably developed out of Handed or Ape-footed Marsupials 
(Pedimana), which are surprisingly like them in the trans- 
formation of their hinder feet into grasjjing hands. The 
primaeval primary forms themselves (which probably origi- 
nated in the eocene period) are of course long siace extinct, 
as are also the greater portion of the transition-forms between 
them and aH the other orders of Deciduata. However, 
individual remnants of the latter are preserved among the 
Semi-apes of the present day. Among these, the remarkable 
Finger-animal of Madagascar (Chiromys madagascariensis) 
constitutes the remnant of the group of the Leptodac- 
tyla and the transition to Rodents. The strange flyina 
lemur in the South Sea and Sunda islands (Galeopitheeus), 
the only remnant of the group of Pteropleura, forms a 
perfect intermediate stage between Semi-apes and Bats. 
The long-footed Semi-apes (Tarsius, Otolicnus) constitute 
the last remnant of that primary branch (Macrotarsi) out of 
which the Insectivora developed. The short-footed forms 
(Brachytarsi) are the medium of connection between them 
and genume Apes. The Short-footed Semi-apes comprise 



the long-tailed Lemur, the short-tailed Lichanotus, and 
the Stenops, the latter of which seems to be very closely 
aUied to the probable ancestors of man among the Semi- 
apes. The short-footed as weU as the long-footed Prosimise 
live widely distributed over the islands of southern Asia 
and Africa, more especially in Madagascar ; some live also 
on the continent of Africa. No Semi-ape, either living or 
in a fossil state, has as yet been found in America. They 
all lead a solitary, nocturnal kind of life, and climb about 
on trees. (Compare vol. i. p. 361.) 

Among the six remaining orders of Deciduata, all of which 
are probably derived from long since extinct Semi-apes, the 
order of Gnaiving animals (Rodentia), which is rich in 
forms, has remained at the lowest stage. Among these the 
squirrel-liJce animals (Sciuromorpha) stand nearest akin to 
the Pedimanous Marsupials. Out of this primary group 
the raouse-like animals (Myomorpha) and the porcupine- 
liJce animals (Hystricomorpha) developed probably as two 
diverging branches, the former of which are directly connected 
with the squirrel-like animals, by the eocene Myoxida, the 
latter by the eocene Psammoryctida. The fourth sub-order, 
the hare-like animals (Lagomorpha), probably developed 
only at a later period out of one of the other three sub-orders. 

Very closely allied to the Eodentia is the remarkable 
order of Pseudo-hoofed ani'nials (Chelophora). Of these there 
now live but two genera, indigenous to Asia and Africa, 
namely, Elephants (Elephas), and Rock Conies (Hyrax). 
Both have hitherto generally been classed among real 
Hoofed animals, or Ungulata, with which they agree in the 
formation of the feet. But an identical transformation of 
nails or claws into hoofs occurs also in genuine Rodentia 


and in certain hoofed Eodentia (Subungulata) whicli live 
exclusively in South America. Beside smaller forms (for 
example, guinea pigs and gold hares) the Subungulata also 
include the largest of all Eodentia, namely, the Capybara 
Rats, which are about four feet in length. The Rock Conies, 
which are externally very nearly akin to Rodents, especially 
to the hoofed Rodents, were formerly classed among 
Rodentia by some celebrated zoologists, as an especial sub- 
class (Lamnungia). Elephants, on the other hand, when not 
classed among Hoofed animals, were generally considered 
as the representatives of a special order which were called 
Trunked animals (Proboscidea). But the formation of the 
placentas of Elephants and of Hyrax agree in a remark- 
able manner, and are entirely distinct from those of Hoofed 
animals. These latter never possess a deeidua, whereas 
Elephants and Hyrax are genuine Deciduata. Their placenta 
is indeed not of the form of a disc, but of a girdle, as in 
the case of Animals of Prey; it is very possible that the 
girdle-shaped placenta is but a secondary development of 
the discoplacenta. Thus, then, it might be thought that 
the Pseudo-hoofed animals have developed out of a branch 
of the Rodentia, and in a similar manner perhaps the 
Camivora out of a branch of the Insectivora. At aU 
events, Elephants and Hyrax in many respects, especially 
in the formation of important skeletal parts, of the limbs, 
etc., are more closely allied to the Rodentia, and more 
especially to hoofed Rodentia, than to genuine Hoofed 
animals. Moreover several extinct forms, especially the 
remarkable South American Arrow-toothed animals (Toxo- 
dontia), stand in many respects mid-way between Elephants 
and Rodentia. That the stiU living Elephants and Hyrax 


are but the last survivors of a group of Pseudo-hoofed 
animals, which was once rich in forms, is proved not only 
by the very numerous fossil species of Elephants and Masto- 
don (some of which are even larger, others also much 
smaller than the Elephants of the present day), but also by 
the remarkable miocene Dinotheria (Gonyognatha), between 
which and their next kindred, the Elephants, there must be 
a long series of unknown connecting intermediate forms. 
Taking aU things into consideration, the most probable 
hypothesis which can be established at present as to the 
origin and the relationship of Elephants, Diaotheria,Toxodon, 
and Hyrax is, that they are the last survivors of a group 
of Pseudo-hoofed animals rich in forms, which developed 
out of the Rodentia, and probably out of relatives of the 

The order of Insect Eaters (Insectivora) is a very ancient 
group, and is next akin to the common extiuct primary 
form of the Deciduata, as weU as to the Semi-apes of the 
present day. It has probably developed out of Semi-apes 
which were closely allied to the Long-footed Lemurs (Macro- 
tarsi) of the present day. It is separated into two orders, 
Menotyphla and Lipotyphla ; the Menotyphla are probably 
the older of the two, and are distinguished from the Lipo- 
typhla by possessing an intestinal coecum, or typhlon. The 
Menotyphla include the climteng Tupajas of the Sunda Isles, 
and the leaping Macroscelides of Africa. The Lipotyphla are 
represented in our country by shrew mice, moles, and hedge- 
hogs. The Insectivora, in the formation of their jaws and 
their mode of life, are nearly akin to Camivora, but are, 
on the other hand, by their discoplacentas and by their 
■(arge seminal vesicles, allied to Rodents. 


It is probable that the order of Rapacious animals (Gar- 
naria) developed out of a long since extinct branch, of 
Insectivora, at the beginning of the Eocene period. It 
is a natural group, very rich in forms, but still of very 
uniform organization. The Rapacious animals are some- 
times also called Girdle-placentals (Zonoplaccntals), although 
the Pseudo-hoofed animals (Chelophora), in the same way, 
also deserve tliis designation. But as the latter, in other 
resjjects, are more closely allied to the Rodentia than to 
Carnaria, we have already discussed them in connection 
with the former. Animals of prey are divided into two, 
externally very different, but internally very closely related, 
sub-orders, namely, Land animals of prey and Marine animals 
of prey. The Land animals of prey (Garni vora) comprise 
bears, dogs, cats, etc., whose pedigree can be approximately 
guessed at by means of many extinct intermediate forms. 
The Marine animals of prey, or Seals (Pinnipedia), com- 
prise sea bears, sea dogs, sea lions, and walruses. Althoui^h 
marine animals of prey appear externally very unlike land 
animals of prey, yet by their internal structure, their jaw 
and their peculiar girdle-shaped placenta, they are very 
nearly akin to them, and have evidently originated out 
of a branch of them, probably out of a kind of weasel 
(Mustelina). Even at the present day the fish otters 
(Lutra), and stiU more so the sea otters (Enhydris), present 
a direct form of transition to Seals, and clearly show how 
the bodies of land Garnivora are transformed into the shape 
of a Seal, by adaptation to an aquatic life, and how the 
steering fijas of marine rapacious animals have arisen out 
of the legs of the former. The latter consequently stand 
in the same relation to the former as do the Whales to 


Hoofed animals among the Indeciduata. In the same way 
as the river-horse at present stands midway between the 
extreme branches of oxen and sea oxen, the sea otter still 
forms a surviving intermediate stage between the widely 
separated branches of dogs and sea dogs. In both cases 
the complete transformation of the external form, conse- 
quent upon adaptation to entirely different conditions of 
life, has not been able to efface the solid foundation of the 
inherited internal peculiarities. 

According to Huxley's opinion, which has -already been 
quoted, only the Herbivorous Whales (Sirenia) are derived 
from Hoofed animals ; on the other hand, the Carnivorous 
Cetacea (Sarcoceta) are derived from the marine animals of 
prey; the Zeuglodonts would form a transition between the 
two latter. But in this case it would be difficult to under- 
stand the close anatomical relations which exist between 
the Herbivorous and Carnivorous Cetacea. The strange 
peculiarities in the internal and external structure which 
so strikingly distinguish the two groups from all other 
mammals would then have to be regarded only as analogies 
(caused by the same kinds of adaptation), not as homologies 
(transmitted from a common primary form). The latter, 
however, strikes me as being by far the more probable, and 
hence I have left all the Cetacea among the Indeciduata as 
one group of kindred origin. 

The remarkable order of Flying Maniinals, or Bats 
(Chiroptera), stands near to tlie Carnaria as well as to the 
Insectivora. It has become strikingly transformed by adap- 
tation to a flying mode of life, just as marine animals of 
prey have become modified by adaptation to a swimming 
mode of life. This order probably also originated out of 


the Semi-apes, with wliich it is even at present closely 
allied, through the flying lemurs (Galeopithecus). Of the 
two orders of flying animals, the insect-eating forms, or 
flying mice (Nycterides), probably developed out of those 
eating fruits, or flying foxes (Pterocynes) ; for the latter are, 
in many ways, more closely allied to Semi-apes than are the 

We have now siiU to discuss the genuine Apes (Simise) 
as the last order of Mammals; but as, according to the 
zoological system, the human race belongs to this order, and 
as it undoubtedly developed historically out of a branch 
of this order, wo shall devote a special chapter to a more 
careful examination of its pedigree and history. 


The Application of the Theory of Descent to Man. — Its Immense Importance 
and Logical Necessity. — Man's Position in the Natural System of 
Animals, among Disco-placental Animals. — Incorrect Separation of 
the Eimana and Quadrumana^ — Correct Sepai'ation of Semi-apes 
from Apes. — Man's Position in the Order of Apes. — Narrow.noeed Apes 
(of the Old World) and Flat-nosed Apes (of America). — Difference of 
the two Groojis. — Origin of Man from Narrow-nosed Apes. — Human 
Apes, or Anthropoides. — African Human Apes (GoriUa and Chimpanzee) . 
— ^Asiatic Human Apes (Orang and Gibbon). — Comparison between the 
different Human Apes and the different Eaces of Men.— Survey of the 
Series of the Progenitors of Man. — Invertebrate Progenitors (Frochor. 
data) and Vertebrate Progenitors. 

Of all the individual questions answered by tlie Theory of 
Descent, of all the special inferences drawn from it, there is 
none of such importance as the ajiplication of this doctrine 
to Man himself As I remarked at the beginning- of this 
treatise, the inexorable necessity of the strictest logic forces 
us to draw the special deductive conclusion from the general 
inductive law of the theory, that Man has developed 
gradually, and step by step, out of the lower Vertebrata, 
and more immediately out of Ape-like Mammals. That 
this doctrine is an inseparable part of the Theory of 
Descent, and hence also of the universal Theory of Develop- 
ment in general, is recognized by all thoughtful adherents 


of the theory, as well as by all its opponents who reason 

But if the doctrine be true, then the recognition of the 
animal origin and pedigree of the human race will neces- 
sarily affect more deeply than any other progress of the 
human mind the views we form of all human relations, 
and the alms of all human scienca It must sooner 
or later produce a complete revolution in the conception 
entertained by man of the entire universe. I am firmly 
convinced that in future this immense advance in our know- 
ledge will be regarded as the beginning of a new period 
of the development of Mankind. It can only be com- 
pared to the discovery made by Copernicus, who was the 
first who ventured distinctly to express the opinion, that 
it was not the sun which moved round the earth, but the 
earth round the sun. Just as the geocentric conception 
of the universe — namely, the false opinion that the earth 
was the centre of the universe, and that all its other por- 
tions revolved round the earth — ^was overthrown by the 
system of the universe established by Copernicus and his 
followers, so the anthropocentric conception of the universe 
— the vain delusion that Man is the centre of terrestrial 
nature, and that its whole aim is merely to serve him — 
is overthrown by the application (attempted long since by 
Lamarck) of the theory of descent to Man. As Copernicus' 
system of the universe was mechanically established by 
Newton's theory of gravitation, we see Lamarck's theory 
of descent attain its causal establishment by Darwin's 
theory of selection. This comparison, which is very in- 
teresting in many respects, I have discussed in detail 


In order to carry out this extremely important appli- 
cation of the Theory of Descent to man, with the necessary 
impartiality and objectivity, I must above aU beg the 
reader (at least for a short time) to lay aside all traditional 
and customary ideas on the "Creation of Man," and to 
divest himself of the deep-rooted prejudices concerning 
it, which are implanted in the mind in earliest youth. If 
he fail to do this, he cannot objectively estimate the weight 
of the scientific arguments which I shall bring forward 
in favour of the animal derivation of Man, that is, of 
his origin out of Ape-like Mammals. We cannot here 
do better than imagine ourselves with Huxley to be the 
inhabitants of another planet, who, taking the opportunity 
of a scientific journey through the universe, have arrived 
upon the earth and have there met with a peculiar two- 
legsred mammal called Man, diffused over the whole earth 
in great numbers. In order to examine him zoologically, 
we should pack a number of the individuals of different 
ages and from different lands (as we should do with the 
other animals collected on the earth) into large vessels 
fiUed with spirits of wine, and on our return to our own 
planet we should commence the comparative anatomy of all 
these terrestrial animals quite objectively. As we should 
have no personal interest in Man, in a creature so entu-ely 
different from ourselves, we should examine and criticise 
him as impartially and objectively as we should the 
other terrestrial animals. In doing this we should, of 
course, in the first place refrain from all conjectures and 
speculations on the nature of his soul, or on the spiritual 
side of his nature, as it is usually called. We should 
occupy ourselves solely with his bodily structure, and with 


that natural conception of it wliich is offered by the history 
of his individual development. 

It is evident that in order correctly to determine Man's 
position among the other terrestrial organisms we must, 
in the fii'st place, follow the guidance of the natural 
system. We must endeavour to determine the position 
which belongs to Man in the natural system of animals 
as accurately and distinctly as possible. "We shaR 
then, if in fact the theory of descent be correct, be able 
from his position in the system to determine the real 
primary relationship, and the degree of consanguinity 
connecting Man with the animals most like him. The 
hypothetical pedigree of the human race will then follow 
naturally as the final result of this anatomical and system- 
atic inquiry. 

Now if, by means of comparative anatomy and ontogeny, 
we seek for man's position in that Natural System of animals 
which formed the subject of the last two chapters, the 
incontrovertible fact will at once present itself to us, that 
man belongs to the tribe, or phylum, of the Vertebrata. 
Every one of the characteristics, which so strikingly distin- 
guish aU the Vertebrata from all Invertebrata, is possessed 
by him. It has also never been doubted that of aU the 
Vertebrata the Mammals are most closely allied to Man, 
and that he possesses all the characteristic features distin- 
guishing them from all other Vertebrata. If then we 
further carefully examine the three different main groups 
or sub-classes of Mammals — the inter-connections of which 
were discussed in our last chapter — there cannot be the slight- 
est doubt that Man belongs to the Placentals, and shares 
with all other Placentals, the important characteristics 

man's place in classification. 267 

which distinguish them from Marsupials and from Cloacals. 
Finally, of the two main groups of placental Mammals, 
the Deciduata and the Indeeiduata, the group of Deciduata 
doubtless includes Man. For the. human embryo is de- 
veloped with a genuine decidua, and is thus absolutely 
distinguished from all the Indeeiduata. Among the 
Deciduata we distinguish two legions, the Zonoplacentalia, 
with girdle-shaped placenta (Beasts of Prey and Pseudo- 
hoofed animals), and the Discoplacentalia, with disc-shaped 
placenta (all the remaining Deciduata). Man possesses a 
disc-shaped placenta, like all Discoplacentalia ; and thus our 
next question must be. What is man's position in this 
group ? 

In the last chapter we distinguished the following five 
orders of Discoplacentalia : (1) Semi-apes ; (2) Rodents ; (3) 
Insectivora; (4) Bats; (5) Apes. The last of these five orders, 
that of Apes, is, as every one knows, in every bodily featmre 
far more closely allied to Man than the four others. Hence 
the only remaining question now is, whether, in the system 
of animals, Man is to bo directly classed in the order of 
genuine Apes, or whether he is to be considered as the 
representative of a special sixth order of Discoplacentalia, 
allied to, but more advanced than, that of the Apes. 

Linnasus in his system classed Man in the same order 
with genuine Apes, Semi-apes, and Bats, which he called 
Primates ; that is, lords, as it were the highest dignitaries 
of the animal kingdom. But Blumenbach, of Gottingen, 
separated Man as a special order, under the uame of Bimana, 
or two-handed, and contrasted him with the Apes and 
Semi-apes under the name of Quadrumana, or four-handed. 
This classification was also adopted by Cuvier and, conse- 


quently, by most subsequent zoologists. It was not until 
1863 that Huxley, in his excellent work, the " Evidence as 
to Man's Place in Nature," ^^ showed that this classification 
was based upon erroneous ideas, and that the so-called 
" four-handed " Apes and Semi-apes are " two-handed " as 
much as man is himself. The difference between the foot 
and hand does not consist in the j^^i-ysiological peculiarity 
that the first digit or thumb is opposable to the four other 
digits or fingers in the hand, and is not so in the foot, for 
there are wild tribes of men who can oppose the first or 
large toe to the other four, just as if it were a thumb. 
They can therefore use their " grasping foot " as well as a 
so-called " hinder hand," like Apes. The Chinese boatmen 
row with this hinder hand, the Bengal workmen weave 
with it. The Negro, in whom the big toe is especially 
strong and freely moveable, when climbing seizes hold of 
the branches of the trees with it, just like the "four- 
handed " Apes. Nay, even the newly born children of the 
most highly developed races of men, during the first months 
of their life, grasp as easily with the "hinder hand" as 
with the "fore hand," and hold a spoon placed in its 
clutch as firmly with their big toe as with the thumb! 
On the other hand, among the higher Apes, especially the 
gorilla, hand and foot are differentiated as in man. (Com- 
pare Plate IV.) 

The essential difference between hand and foot is there- 
fore not physiological, but morphological, and is determined 
by the characteristic structure of the bony skeleton and of 
the muscles attached to it. The ankle-bones differ from 
the Avrist-bones in arrangement, and the foot possesses 
three special muscles not existing in the hand (a short 


flexor muscle, a short extensor muscle, and a long fibular 
muscle). In all these respects, Apes and Semi-apes entirely 
agree with man, and hence it was quite erroneous to 
separate him from, them as a special order on account 
of the stronger differentiation of his hand and foot. It is 
the same also with all the other structural features by 
means of which it was attempted to distinguish Man from 
Apes ; for example, the relative length of the limbs, the 
structure of the skull, of the brain, etc. In all these respects, 
without exception, the differences between Man and the 
higher Apes are less than the corresponding differences 
between the higher and the lower Apes. Hence Huxley, 
for reasons based on the most careful and most accurate 
anatomical comparisons, arrives at the extremely important 
conclusion — " Thus, whatever system of organs be studied, 
the comparison of their modifications in the Ape series leads 
to one and the same result, that the structural differences 
which separate Man from the Gorilla and Chimpanzee are 
not so great as those which separate the Gorilla from the 
lower Apes." In accordance with this, Huxley, strictly 
following the demands of logic, classes Man, Apes, and Semi- 
apes in a single order, Primates, and divides it into the 
following seven families, which are of ahuost equal systematic 
value : (1) Anthropini (Man) ; (2) Catarrhini (genuine Apes 
of the Old World); (3) Platyrrhini (genuine American Apes) ; 
(4) Arctopitheci (American clawed Apes); (5) Lemurini 
(short-footed and long-footed Semi-apes, p. 255) ; (C) Chir- 
omyini (p. 256) ; (7) Galeopithecini (Flying Lemurs, p. 256). 
If we wish to arrive at a natural system, and conse- 
quently at the pedigree of the Primates, we must go a step 
further still, and entirely separate the Semi-apes,or Prosimiaj, 



Of the Families and Genera of Apes. 








Si/stematic Name 


the. Genera. 

APES (Platyrrlimi). 

A. ^latgtttjini 
Jaitf) clafas 

B. 5!3IatgrtI)tm 
initfj iluixt 

I. Silky apes 

II. Mat-nosed, 
•witliout pre- 
hensile tail 
III. Flat-nosed, 
with preliensile 

1. Brush ape 

2. Lion apo 

1. Midas 

2. Jaochus 

3. Squirrel ape 3. 

4. Leaping apa 4. 

5. Nocturnal ape 5. 

6. Tail ape 6. 

7. Rolling ape 7. 

8. Climbing ape 8. 

9. Woolly ape 9. 
^ 10. Howling ape 10. 









APES (Catarrhiai). 

C. araitcU 



D. Caillcss 


( IV. TaUed Catar. 
rhinij with 
cheek-pou ches 


V. Tailed Catar- 

rhini, without 



TI. Human apes 

Til. Men 


11. Pavian 
' 12, Macaque 
'13. Sea cat 

1 14. Holy ape 

( 15. Short ape 

f 16. Nose ape 

/l?. Gibbon 

nS. Orang-Outan 18. 

j 19. Chimpanzee 19. 

\20. Gorilla 20. 

1 21. Ape-liko man, 21. 

( or speechless man 

(22. Talking man 22. 

11. Cynocephalus 

12. Inuus 

13. Cercopithecus 







Straight-haired men 

Woolly-haired men 

Speechless men (AlaVC)) or 
Ape-like men (Fithecantliropi) 



Man-like Apes 

' Orang 


Man-like Apes 

Silk apes 

Man=likt aprs 

Nose apea 



illatejiosrtf apts 

Tall apes 

Sea cat 


Tailed Narrow-nosed apea 
Catafrhina menocerca 







(Huxley's last three families), from Genuine Apes, or Simise 
(the first four families). For, as I have already shown in my 
General Morphology, and explained in the last chapter, the 
Semi-apes differ in many and important respects from 
Genuine Apes, and in their individual forms are more 
closely allied to the various other orders of Discoplacentalia. 
Hence the Semi-apes must probably be considered as the 
remnants of the common primary group, out of which the 
other orders of Discoplacentalia, and, it may be, all De- 
ciduata, have developed as two diverging branches. (Gen. 
Morph. ii. pp. 148 and 153.) But man cannot be sepa- 
rated from the order of Genuine Apes, or Simiac, as he is 
in every respect more closely allied to the higher Genuine 
Apes than the latter are to the lower Genuine Apes. 

Genuine Apes (Simiae) are universally divided into two 
perfectly natural groups, namely, the Apes of the New 
World, or American Apes, and the Apes of the Old World, 
which are indigenous to Asia and Africa, and which for- 
merly also existed in Europe. These two classes differ prin- 
cipally in the formation of the nose, and they have been 
named accordingly. American Apes have flat noses, so that 
the nostrils are in front, not below; hence they are called 
Flat Hoses (Platyrrhini). On the other hand, the Apes of 
the Old World have a narrow cartilaginous bridge, and the 
nostrils turned downwards, as in man ; they are, therefore, 
called Narroiu Noses (Catarrhini). Further, the jaw, 
which plays an important part in the classification of 
Mammals, is essentially distinct in these two groups. All 
Catarrhinae, or Apes of the Old World, have exactly the 
same jaws as Man, namely, in each jaw four incisors above 
and below, then on each side a canine tooth and five cheek 


teeth, of wHcli two are pre-molars and three molars, 
altogether thuiy-two teetL But aU Apes of the New 
World, all Platyrrhini, have four more cheek teeth, namely, 
three pre-molars and three molars on each side, above and 
below: they consequently possess thu-ty-six teeth. Only 
one small group forms an exception to this nile, namely, 
the Arctopitheci, or Clawed Apes, in whom the third molar 
has degenerated, and they accordingly have on each half of 
their jaw three pre-molars and two molars. They also 
differ from the other Platyrrhini by having claws on the 
fingers of their hands and the toes of their feet, not nails 
like Man and the other Apes. This small group of South 
American Apes, which includes among others the well- 
known pretty little Midas-monkey and the Jacchus, must 
probably be considered only as a peculiarly developed 
lateral branch of the Platyrrhini. 

Now, if we ask what evidence can be drawn, as to the 
pedigree of Apes, from the above facts, we must con- 
clude that all the Apes of the New World have developed 
out of one tribe, for they aU possess the characteristic jaw 
and the nasal formation of the PlatyrrhinL In like 
manner it follows that all the Apes of the Old World must 
be derived from one and the same common primary form, 
which possessed the same formation of nose and jaw as 
all the stiU living CatarrhinL Further, it can scarcely 
be doubted that the Apes of the New World, taken as an 
entire tribe, are either derived from those of the Old World, 
or (to express it more vaguely and cautiously) both are 
diverging branches of one and the same tribe of Apes. We 
also arrive at the exceedingly important conclusion — 
which is of the utmost significance in regard to Man's dis- 


tribution on the earth's surface — that Man has developed 
out of the Catarrhini. For we cannot discover a zoological 
character distinguishing him in a higher degree from the 
allied Apes of the Old World than that in which 
the most divergent forms of this group are distinguished 
from one another. This is the important result of 
Huxley's careful anatomical examination of the question, 
and it cannot be too higlily estimated. The anatomical 
differences between Man and the most human-like Catar- 
rhini (Orang, Gorilla, Chimpanzee) are in every respect less 
than the anatomical differences between the latter and the 
lowest stages of Catarrhini, more especially the Dog-like 
Baboon. This exceedingly important conclusion is the 
result of an impartial anatomical comparison of the different 
forms of Catarrhini 

If, therefore, we recognise the natural system of animals 
as the guide to our speculations, and establish upon it our 
pedigree, we must necessarily come to the conclusion that the 
hurnun race is a small branch of the group of Catarrhini, 
and has developed out of long since extinct Apes of this group 
in the Old World. Some adherents of the Theory of Descent 
have thought that the American races of Men have de- 
veloped, independently of those of the Old World, out of 
American Apes. I consider this hypothesis to be quite 
erroneous, for the complete agreement of all mankind with 
the Catan-hini, in regard to the characteristic formation of 
the nose and jaws, distinctly proves that they are of the 
same origin, and that they developed out of a common 
root after the Platyrrhini, or American Apes, had already 
branched off from them. The primaeval inhabitants of 
America, as is proved by numerous ethnographical facts. 


immigrated from Asia, and partly perhaps from Polynesia 
(or even from Europe). 

There stiU exist great difficulties in establishing an 
accurate pedigree of the Human Kace; this only can "we 
further assert, that the nearest progenitors of man were 
tail-less Catarrhini (Lipocerca), resembling the stiU living 
Man-like Apes. These evidently developed at a late 
period out of tailed Catarrhini (Menocerca), the original 
form of Ape. Of those tail-lesa Catarrhini, which are now 
frequently called Man-like Apes, or Anthropoides, there 
still exist four different genera containing about a dozen 
different species. 

The largest Man-like Ape is the famous Gorilla (called 
Gorilla engena, or Pongo gorilla), which is indigenous to 
the tropics of western Africa, and was first discovered 
by the missionary. Dr. Savage, in 1847, on the banks of 
the river Gaboon. Its nearest relative is the Chim- 
panzee (Engeco troglodytes, or Pongo troglodytes), also 
indigenous to western Africa, but considerably smaller 
than the Gorilla, which surpasses man in size and strength. 
The third of the three large Man-like Apes is the Orang, or 
Orang Outang, indigenous to Borneo and the other Sunda 
Islands, of which two kindred species have recently been 
distinguished, namely, the large Orang (Satyrus orang, or 
Pithecus satyrus) and the small Orang (Satyrus morio, or 
Pithecus morio). Lastly, there stiU exists in southern Asia 
the genus Gibbon (Hylobates), of Avhich from four to eight 
different species are distinguished. They are considerably 
smaller than the three first-named Anthropoides, and in 
most characteristics differ more from Man. 

The tad-less Man-like Apes — especially since we have 


become more intimately acquainted with the Gorilla, and 
its connection Avith Man by the application of the Theory 
of Descent — have excited such universal interest, and called 
forth such a flood of writings, that there is no occasion for 
me here to enter into any detail about them. The reader 
will find their relations to Man fully discussed in the ex- 
cellent works of Huxley,^'' Carl Vogt,^' Biichner,*^ and 
Rolle.^ I shall therefore confine myself to stating the 
most important general conclusion resulting from their 
thorough comparison with Man, namely, that each one of 
the four Man-like Apes stands nearer to Man in one or 
several respects than the rest, but that no one of them can 
in every respect be called absolutely the most like Man. 
The Orang stands nearest to Man in regard to the formation 
of the brain, the Chimpanzee in importaint characteristics 
in the formation of the skull, the Gorilla in the development 
of the feet and hands, and, lastly, the Gibbon in the forma- 
tion of the thorax. 

Thus, from a careful examination of the comparative 
anatomy of the Anthropoides, we obtain a similar result to 
that obtained by Weisbach, from a statistical classification 
and a thoughtful comparison of the very numerous and 
careful measurements which Scherzer and Schwarz made 
of the different races of Men during their voyage in the 
Austrian fiigate Novara round the earth. Weisbach com- 
prises the final result of his investigations in the follow- 
ing words : " The ape-lilce characteristics of Man are by 
no means concentrated in one or another race, but are 
distributed in particular parts "of the body, among the 
different races, in such a manner that each is endowed 
with some heirloom of this relationship — one race more so, 


another less, and even we Europeans cannot claim to be 
entirely free from evidences of this relationship." * 

I must here also point out, what in fact is self-evident, 
that not one of all the still living Apes, and consequently 
not one of the so-called Man-like Apes, can be the pro- 
genitor of the Human Race. This opinion, in fact, has 
never been maintained by thoughtful adherents of the 
Theory of Descent, but it has been assigned to them by their 
thoughtless opponents. The Ape-like progenitors of the 
Human Race are long since extinct. We may possibly still 
find their fossil bones in the tertiary rocks of southern Asia 
or Africa. In any ease they will, in the zoological system, 
have to be classed in the group of tail-less I^ arrow-nosed 
Apes (Catarrhini Lipocerci, or Anthropoides. 

The genealogical hypotheses, to which we have thus far 
been led by the application of the Theory of Descent to 
Man, present themselves to every clearly and logically rea- 
soning person as the direct results from the facts of com- 
parative anatomy, ontogeny, and palseontology. Of course 
our phylogeny can indicate only in a very general way the 
outlines of the human pedigree. Phylogeny is the more in 
danger of becoming erroneous the more rigorously it is 
applied in detail to special animal forms known to us. 
However, we can, even now, with approximate certainty 
distinguish at least the following twenty-two stages of the 
ancestors of Man. Fourteen of these stages belong to the 
Vertebrata, and eight to the Invertebrate ancestors of Man 

* Wcisbach : " Novara-K«ise," Anthropholog, Theil. 



(Comp. Ch. XX., XXI. ; Plate XIV. and p. 22). 


FmsT Stage : llonera. 

The most ancient ancestors of Man, as of aU other 
organisms, were living creatures of the simplest kind 
imaginable, organisms without organs, like the still 
living Monera. They consisted of simple, homogeneous, 
structureless and formless little lumps of mucous or 
albuminous matter (protoplasm), like the still living Pro- 
tamoeba primitiva. (Compare vol. i. p. 186, Fig. 1.) The form 
value of these most ancient ancestors of man was not even 
equal to that of a cell, but merely that of a cytod (compare 
vol L p. 347); for, as in the case of all Monera, the little lump 
of protoplasm did not as yet possess a cell-kernel. The first 
of these Monera originated in the beginning of the Lauren- 
tian period by spontaneous generation, or archigony, out of 
so-called "inorganic combinations," namely, out of simple 
combinations of carbon, oxygen, hydrogen, and nitrogen. 
The assumption of this spontaneous generation, that is, of 
a mechanical origin of the first organisms from inorganic 
matter, has been proved in our thirteenth chapter to be 
a necessary hypothesis. (Compare voL i. p. 338.) A direct 


"proof of the earlier existence of this most ancient ancestral 
stage, based upon the fundamental law of biogeny, is pos- 
sibly still furnished by the circumstance that, according 
to the assertions of many investigators, in the beginning 
of the development of the ^gg, the cell-kernel, or nucleus, 
disappears, and the egg-cell thus relapses to the lower stage 
of the cytod (Monerula, p. 124< ; relapse of the nucleated 
plastid into a non-nucleated condition). The assumption 
of this first stage is necessary for most important general 

Second Stage : AmoebaB. 

The second ancestral stage of Man, as of all the higher 
animals and plants, is formed by a simple cell, that is, a little 
piece of protoplasm enclosing a kernel There still exist 
large numbers of similar " single-celled organisms." Among 
them the common, simple Aiaoebse (vol. i. p. 188, Fig. 2) 
cannot have been essentially different from these progenitors. 
The form, value of every Amoeba is essentially the same as 
that still possessed by the egg of Man, and by the egg of 
all other animals. (Vol. i. p. 189, Fig. 3.) The naked egg- 
ceUs of Sponges, which creep about exactly like Amoebae, 
cannot be distinguished from them. The egg-cell of Man, 
which like that of most other animals is surrounded by a 
membrane, resembles an enclosed Amoeba. The first single- 
ceUed animals of this kind arose out of Monera by the 
difierentiation of the inner kernel and the external proto- 
plasm; they lived in the earher Primordial period. An 
irrefutable proof that such single-celled prim£eval animals 
really existed as the direct ancestors of Man, is furnished 
according to the fundamental law of biogeny (vol. i. p. 309) 


by the fact that the human egg is nothing more than a 
simple cell (Compare p. 124.) 

Third Stage : SynamcebsB. 

In order to form an approximate conception of the organ- 
isation of those ancestors of Man which first developed out 
of the single-celled Primseval animals, it is necessary to trace 
the changes undergone by the human egg in the beginning 
of its individual development. It is just here that ontogeny 
guides us with the greatest certainty on to the track of 
phylogeny. We have ah-eady seen that the egg of Man (in 
the same way as that of all other Mammals), after fructifica- 
tion has taken place, falls by self-division into a mass of 
simple and equi-formal Amoeba-like cells (vol. i. p. 190, 
Fig. 4 B.) All these divided globules are at first exactly like 
one another, naked cells containing a kernel, but without 
covering ; in many animals they show movements like those 
of the Amoebaa. This ontogenetic stage of development 
which we called Morula (p. 125), on account of its mulberry 
shape, is a certain proof that in the early primordial period 
there existed ancestors of man which possessed the forTn 
value of a mass of homogeneous, loosely connected cells. 
They may be called a community of Amcebce (Synamoebse). 
(Compare p. 127.) They originated out of the single-celled 
Primseval animals of the second stage by repeated self- 
division and by the permanent nnion of the products of 
this division. 

FouKTH Staob : Ciliated larva (Planaada). 

In the course of the ontogenesis of most of the lower 
animals, and also in that of the lowest Vertebrate animals, 


the Lanceolate Animals, or Amphioxus, there first develops 
out of the Morula (Frontispiece, Fig. 3) a ciliated larva 
(planula). Those cells, lying on the surface of the homo- 
geneous mass of ceUs, extend hair -like processes, or fringes 
of hairs, which by striking against the water keep the 
whole body rotating. The round many-celled bodj' thus 
becomes differentiated, in that the external cells covered 
with cilia differ from the non-ciliated internal cells. 
(Frontispiece, Fig. 4). In Man and in all other Vertebrate 
animals (with the exception of the Amphioxus), as well 
as in all Arthropoda, this stage of the ciliated larva has been 
lost, in the course of time, by abbreviated inheritance. 
There must, however, have existed ancestors of Man in the 
early Primordial period which possessed the form value of 
these ciliated larvse (Plansea, p. 125). A certain proof of 
this is furnished by the Amphioxus, which is on the one 
hand related by blood to Man, but on the other has retained 
down to the present day the stage of the planula. 

FiPTH Stage : Primaeval Stomach Animals (Gastraeada). 

In the course of the individual development of Am- 
phioxus, as well as in the most different lower animals, 
there first arises out of the planula the extremely important 
form of larva whicli we have named stomach larva, or 
gastrula (p. 126 ; Frontispiece, Fig. 5, 6). According to the 
fundamental law of biogeny this gastrula proves the former 
existence of an independent form of primaeval animal of 
the same structure, and this we have named primsoval 
stomach animal, or Gastrtsa (pp. 127, 128). These 
Gastrceada must have existed during the older Primordial 
period, and they must have also included the ancestors of 


man. A certain proof of tliis is furnished by tlie AmpHoxus, 
whicli in spite of its blood relationship to Man still passes 
through the stage of the gastrula with a simple intestine 
and a double intestinal waU. (Compare Plate X. Fig. B 4.) 

Sixth Stage : Gliding Worms (Turbellaria). 

The human ancestors of the sixth stage which originated 
out of the Gastrseada of the fifth stage^ were low worms, 
which, of all the forms of worms known to us, were most 
closely allied to the Gliding Worms, or Turbellaria, or at least 
upon the whole possessed their form value. Like the Tur- 
beUaria of the present day, the whole surface of their body 
was covered with cilia, and they possessed a simple body 
of an oval shape, entirely without appendages. These 
acoelomatous worms did not as yet possess a true body- 
cavity (coslom) nor blood. They originated in the early 
primordial period out of the Gastr^ada, by the formation 
of a middle germ-layer, or muscular layer, and also by the 
further differentiation of the internal parts into various 
organs ; more especially the first formation of a nervous 
system, the simplest organs of sense, the simplest organs 
for secretion (kidneys) and generation (sexual organs). The 
proof that human ancestors existed of a similar formation, 
is to be looked for in the circumstance that comparative 
anatomy and ontogeny point to the lower acoelomatous 
Worms as the common primary form, not merely of all 
higher Worms, but also of the four higher tribes of 
animals. Now, of aU the animals known to us, the 
TurbeUaria, which possess neither a body-cavity nor blood, 
are most closely allied to these primeval acoelomatous 
Primary Wonns. 


Seventh Stage : Soft Worms (Scolecida). 

Between the Turbellaria of tlie preceding stage and 
the Sack Worms of the next stage, we must necessarily 
assume at least one connecting intermediate stage. For the 
Tunicata, which of all known animals stand nearest to the 
eighth stage, and the Turbellaria which most resemble the 
sixth stage, indeed both belong to the lower division of the 
unsegmented Worms ; but still these two divisions differ 
so much from one another in their organii^ation, that we 
must necessarily assume the earlier existence of extinct 
intermediate forms between the two. These connecting 
links, of which no fossil remains exist, owing to the soft 
nature of their bodies, we may comprise as Soft Worms, or 
Scolecida. They developed out of the Turbellaria of 
the sixth stage by forming a true body- cavity (a coelom) 
and blood in their interior. It is difficult to say 
which of the still living Coslomati are nearest akin 
to these extinct Scolecida, it may be the Acorn-worms 
(Balanoglossus). The proof that even the direct ancestors 
of man belonged to these Scolecida, is furnished by the 
coinparative anatomy and the ontogeny of Worms and of 
the Amphioxus. The form value of this stage must more- 
over have been represented by several very different inter- 
mediate stages, in the wide gap between Tui-bellaria and 

Eighth Stage : Sack 'Worms (Himatega). 
Under the name of Sack worms, or Himatega, we here 
allude in the eighth place to those Coelomati, out of which 
the most ancient skuU-less Vertebrata were directly devel- 
oped. Among the Coelomati of the present day, the Ascidians 


are the nearest relatives of 'these exceedingly remarkable 
Worms, which connect the widely difFeriag classes of Inver- 
tebrate and Vertebrate animals. That the ancestors of 
man really existed during the primordial period in the form 
of these Himatega, is distinctly proved by the exceedingly 
remarkable and important agreement presented by the 
ontogeny of the Amphioxus and the Ascidia. (Compare Plates 
XII. and XIII., also pp. 152, 200, etc.) From this fact the 
earlier existence of Sack Worms may be inferred ; they of 
aU known worms were most closely related to our recent 
Tunicates, esi^ecially to the freely swimming young forms 
or \a,rvse of the simple Sea-squii^ts (Ascidia, Phallusia). 
They originated out' of the worms of the seventh stage by 
the formation of a dorsal nerve-marrow (medulla tube), 
and by the formation of the spinal rod (chorda dorsalis) 
which lies below it. It is just the position of this central 
spinal rod, or axial skeleton, between the dorsal marrow 
on the dorsal side, and the intestinal canal on the ventral 
side, which is most characteristic of all Yertebrate animals, 
including man, but also of the larvae of the Ascidia. The 
form value of this stage nearly corresponds with that which 
the larvas of the sim.ple Sea-squirts possess at the time 
when they show the beginning of the dorsal marrow and 
spinal rod. (Plate XII. Fig. A 5 : compare the explanation 
of these fig-ures in the Appendix.) 





Ninth Stage : Skull-less Animals (Aorania). 
The series of human ancestors, which in accordance with 
their whole organisation we have to consider as Vertebrate 
animals, begins with the Skull-less animals, or Acrania, of 
whose nature the still living Lancelet (Amphioxus laneeo- 
latus, Plate XII. B, XIII. B) gives us a faint idea. Since 
this little animal in its earliest embryonal state entirely 
agrees with the Ascidia, and in its further development 
shows itself to be a true Vertebrate animal, it forms a direct 
transition from the Vertebrata to the Invertebrata. Even 
if the human ancestors of the ninth stage in many respects 
differed from the Amphioxus — the last surviving representa- 
tive of the Skull-less animals — yet they must have resembled 
it in its most essential characteristics, in the absence of head, 
skull, and brain. SkuU-less animals of such structure — out 
of w^hich animals wth skulls developed at a later period — 
lived during the primordial period, and originated out of 
the Himatega'of the eighth stage by the formation of the 
metamera, or body segments, as also by the further differen- 
tiation of aU organs, especially the more perfect development 
of the dorsal nerve-marrow and the spinal rod lying below 
it. Probably the separation of the two sexes (gonochorism) 
also began at this stage, Tvhereas all the previously men- 
tioned invertebrate ancestors (apart from the 3 — 4 first 


neutral stages) exhibited the condition of hermaphrodites 
(hermaphroditism). (Compare vol. i. p. 196.) The certain 
•proof of the former existence of these skull-less and brain- 
less ancestors of man, is furnished by the comparative 
anatomy and the ontogeny of the Amphioxus and of the 

Tbntu Stage : Single-nostriled Animals (MonorrWna). 

Out of the SkuU-less ancestors of man there arose in the 
first place animals with skuUs, or Craniota-, of the mo':t imper- 
fect nature. The lowest stage of aU stiU living Craniota is 
occupied by the class of round-mouthed animals, or Cyclos- 
toma, namely, the Hag (My^inoidea) and Lampreys (Petro- 
myzontia). From the internal organization of these single- 
nostriled animals, or Monorrhina, we can fonn an approxi- 
mate idea of the nature of the human ancestors of the tenth 
stage. In the former, as also in the latter, skull and brain 
must have been of the simplest form, and many important 
organs, as for example, the swimming bladder, the sympa- 
thetic nerve, the spleen, the jaw skeleton, and both pairs of 
legs, may probably as yet not have existed. However, the 
pouch gills and the round sucking mouth of the Cyclostoma 
must probably be looked upon as purely adaptive charac- 
teristics, which did not exist in the corresponding stage of 
ancestors. The single-nostriled animals originated during 
the primordial period out of the skuU-less animals by the 
anterior end of the dorsal marrow developing into the brain, 
and the anterior end of the dorsal chord into the skuU, 
The certain "proof that such single-nostriled and jawless 
ancestors of man did exist, is found in the " comparative 
anatomy of the Myxinoidea." 


Elevi!nth Stage : Primaeval Fish (Selachii.) 
Of all tnown Vertebrate animals, the ancestors of the 
Primaeval Fish probably shoved most resemblance to the 
stiU living Sharks (Squalacei). They originated out of 
the single-nostriled animals by the division of the single 
nostril into two lateral halves, by the formation of a 
sympathetic nervous system, a jaw skeleton, a swimming 
bladder, and two pairs of legs (breast fins or fore-legs, and 
ventral iSns or hind-legs). The internal organisation of this 
stage may probably, upon the whole, have corresponded to 
the lowest species of Sharks known to us ; the swimming 
bladder was however more strongly developed ; in the case 
of the latter it exists only as a rudimentary organ. They 
lived as early as the Silurian period, as is proved by the 
fossil remains of sharks (teeth and fin spines) from the 
Silurian strata. A certain proof that the Silurian ances- 
tors of man and of all the other double-nostriled animals 
were nearest akin to ^the Selachii, is furnished by the 
comparative anatomy of the latter ; it shows that the 
relations of organisation in all Amphu-rhLna can be derived 
from those of the Selachii 

Twelfth Stage : Mud Fish (Dipneusta). 
Our twelfth ancestral stage is formed by Vertebrate 
animals which probably possessed a remote resemblance to 
the stni living Salamander fish (Ceratodus, Protopterus, 
Lepidosiren, p. 212). They originated out of the Primasval 
fish (probably at the beginning of the palaeolithic, or 
primary period) by adaptation to life on land, and by the 
transformation of the swimming bladder into an air- 
breathing lung, and of the nasal cavity (which now opened 


into the cavity of the mouth) into air passages. The series 
of the ancestors of man which breathed air through lungs 
began at tliis stage. Their organisation may probably in 
many respects have agreed with that of the stiU living 
Ceratodus and Protopterus, but at the same time may 
have been very different. They probably lived at the 
beginning of the Devonian j^eriod. Their existence is 
proved by comparative anatomy, which shows the Dipneusta 
to be an intermediate stage between the Selachii and 

THrRTEENTH Stage : Gilled Amphibians (Sozobranoiia) . 

Out of those Mud Fish, which we considered the primary 
forms of all the Vertebrata which breathe through lungs, 
there developed the class of Amphibia as the main line 
(pp. 205, 216). Here began the five-toed formation of the 
foot (the Pentadactyla), which was thence transmitted to 
the higher Vertebrata, and finally also to Man. The giUed 
Amphibians must be looked u|)on as our most ancient 
ancestors of the class of Amphibia ; besides possessing 
lungs they retained throughout life regular gills, like the 
still living Proteus and Axolotl (p. 218). They originated 
out of the Dipneusta by the transformation of the paddling 
fins into five-toed legs, and also by the moi'e perfect dif- 
ferentiation of various organs, especially of the vertebral 
column. In any case they existed about the middle of the 
palceolithic, or primary period, possibly even before the Coal 
period ; for fossil Amphibia are found in coal. The -proof 
that similar giUed Amphibians were our direct ancestors, is 
given by the comparative anatomy and the ontogeny of 
Amphibia and Mammals, 


FotJEXEENTH SxAGB : Tailed Amphibians (Sozura). 

Our amphibious ancestors which retained their gills 
throughout life, -were replaced at a later period by other 
Amphibia, which, by metamorphosis, lost the gills which 
they had possessed in early life, but retained the tail, as in 
the case of the salamanders and newts of the present day. 
(Compare p. 218.) They originated out of the gilled 
Amphibians by accustoming themselves in early life to 
breathe only through gills, and later in life only through 
lungs. They probably existed even in the second half 
of the primary, namely, during the Permian period, but 
possibly even during the Coal period. The proof of their 
existence lies in the fact that tailed Amphibians form a 
necessary intermediate link between the preceding and 
succeeding stages. 

FiPTBENiH Stage : Primaval Amniota (Protamnia). 

The name Protamnion we have given to the primary 
form of the three higher classes of Vertebrate animals, 
out of which the Proreptilia and the Promammalia developed 
as two diverging branches (p. 222). It originated out 
of unknown tailed Amphibia by the complete loss of the 
gills, by the formation of the amnion, of the cochlea, and 
of the round window in the auditory organ, and of the 
organs of tears. It probably originated in the beginning 
of the mesolithie or secondary period, perhaps even towards 
the end of the primary, in the Permian period. The 
certain proof that it once existed lies in the comparative 
anatomy and the ontogeny of the Amniota ; for all PueptHes, 
Birds, and Mammals, including Man, agi-ee in so many 
important characteristics that they must, with full assur- 


ancGj be admitted to be the descendants of a single eonunon 
primary form, namely, of the Protamnion. 

Sixteenth Stage : Primary Manunals (Promammalia). 

We now find ourselves more at home with our ancestors. 
From the sixteenth up to the twenty-second stage they 
an belong to the large and well known class of Mammals, 
the confines of which we ourselves have as yet not 
transgressed. The common, long since extinct and unknown 
primary forms of all Mammalia, which we have named 
Promammalia, were at all events, of all stiU living animals, 
of the class most closely related to the Beaked animals, or 
Ornlthostoma (Ornithorhynchus, Echidna, p. 233). They 
differed from the latter, however, by the teeth present 
in their jaws. The formation of the beak in the Beaked 
animals of the present day must be looked upon as an 
adaptive characteristic which developed at a later period. 
The Promammalia arose out of the Protamnia (probably 
only at the beginning of the secondary period, namely, in 
the Trias) by various advances in their internal organis- 
ation, as also by the transformation of the epidermal scales 
into hairs, and by the formation of a mammary gland 
which furnished milk for the nourishment of the young 
ones. The certain proof that the Promammalia — inasmuch 
as they are the common primary forms of aU Mammals — 
also belong to our ancestors, lies in the comparative 
anatomy and the ontogeny of Mammalia and Man. 

Seventeenth: Stage : Pouched Animals (Marsnpialia). 

The tliree sub-classes of Mammalia — as we have already 
seen — stand in such a relation to one another that the 


Marsupials, both as regards their anatomy and their 
ontogeny and phylogeny, form the direct transition from the 
Monotrema to Placental animals (p. 247). Consequently, 
human ancestors must also have existed among Marsupials. 
They originated out of the Monotrema — which include 
the primary Mammalia, or Promammalla — by the division of 
the cloaca into the rectum and the urogenital sinus, by the 
formation of a nipple on the mammary gland, and by the 
partial suppression of the clavicles. The oldest Marsupials 
at all events existed as early as the Jura period (perhaps 
even in the Trias), during the Chalk period they passed 
through a series of stages preparing the way for the origin 
of Placentalia. The certain proof of our derivation from 
Marsupials — nearly akin to the still living opossum and 
kanararoo in their essential inner structure— is furnished 
by the comparative anatomy and the ontogeny of 

Eighteenth Stage : Semi-apes (Prosimise). 

The small group of Semi-apes, as wo have already seen, 
is one of the most important and most interesting orders of 
Mammalia. It contains the direct primary forms of Genuiae 
Apes, and thus also of Man. Our Semi-ape ancestors probably 
possessed oidy a very faint external resemblance to the still 
living, short-footed Semi-apes (Brachytarsi), especially the 
Maki, Indri, and Lori (p. 256). They originated (probably 
at the beginning of the Cenolithic, or Tertiary period) out 
of Marsupials of Rat-like appearance by the formation of a 
placenta, the loss of the marsupium and the marsupial 
bones, and by the higher development of the commis- 
sures of the brain. The certain proof that Genuine Apes, 


and hence also our own race, are the direct descendants of 
Semi-apes, is to be found in the comparative anatomy and 
the ontogeny of Placental animals. 

Nineteenth Stage : Tailed Apes (Menocerca). 

Of the two classes of Genuine Apes which developed out 
of the Semi-apes, it is only the narrow-nosed, or Catarrhini, 
which are closely related by blood to Man. Our older 
ancestors from this group probably resembled the still 
living Nose-apes and Holy-apes (Semnopithecus), which 
possess jaws and narrow noses like Man, but have a long 
tail, and their bodies densely covered with hair (p. 271). 
The Tailed Apes with narrow noses (Catarrhini Menocerci) 
originated out of Semi-apes by the transformation of the 
jaw, and by the claws on their toes becoming changed into 
nails; this probably took place as early as the older Tertiary 
period. Tlie certain proof of our derivation from Tailed 
Catarrhini is to be found in the comparative anatomy and 
the ontogeny of Apes and of Man. 

Twentieth Stage : Man-like Apes (Antliropoides). 

Of all still living Apes the large tail-less, narrow-nosed 
Apes, namely, the Orang and Gibbon in Asia, the Gorilla 
and Chimpanzee in Africa, are most nearly akin to Man. 
It is probable that these Man-like Apes, or Antliropoides, 
originated during the Mid-tertiary period, namely, in the 
Miocene period. They developed out of the Tailed Catar- 
rhini of the preceding stage — with which they essentially 
agree — by the loss of the tail, the partial loss of the hairy 


covering, and by the excessive development of that portion 
of the brain just above the facial portion of the skull. 
There do not exist direct human ancestors among the 
Anthropoides of the present day, but they certainly existed 
among the unknown extinct Human Apes of the Miocene 
period. The certain proof of their former existence is 
furnished by the comparative anatomy of Man-hke Apes 
and of Man. 

TWEKiY-FiRST Stage : Ape-lite Men (Pithecanthropi). 

Although the preceding ancestral stage is already so 
nearly akin to genuine Men that we scarcely require to 
assume an intermediate connecting stage, still we can look 
upon the speechless Primaeval Men (Alali) as this inter- 
mediate link. These Ape-like men, or Pithecanthropi, very 
probably existed towards the end of the Tertiary period. 
They oi'iginated out of the Man-like Apes, or Anthropoides, 
by becoming completely habituated to an upright walk, and 
by the corresponding stronger differentiation of both pairs of 
legs. The fore hand of the Anthropoides became the human 
hand, their hinder hand became a foot for walking. 
Although these Ape-like Men must not merely by the 
external formation of their bodies, but also by their internal 
mental development, have been much more akin to real 
Men than the Man-like Apes could have been, yet they did 
not possess the real and chief characteristic of man, namely, 
the articulate human language of words, the corresponding 
development of a higher consciousness, and the formation 
of ideas. The certain proof that such Primaeval Men with- 
out the power of speech, or Ape-like Men, must have 
preceded men possessing speech, is the result arrived at by 


an inquiring mind from comparative philology (from the 
"comparative anatomy" of language), and especially from 
the history of the development of language in every child 
(" glottal ontogenesis ") as weU as in every nation (" glottal 
phylogenesis "). 

Twenty-second Stage : Men (Homiuee). 

Genuine Men, developed out of the Ape-like Men of the 
preceding stage by the gradual development of the animal 
language of sounds into a connected or articulate language, 
of words. The development of this function, of com-se, 
went hand in hand with the development of its organs, 
namely, the higher differentiation of the larynx and the 
brain. The transition from speechless Ape-like Men to 
Genuine or Talking Men probably took place at the begin- 
ning of the Quaternary period, namely, in the Diluvial 
period, but possibly even at an earlier date, in the more 
recent Tertiary. As, according to the unanimous opinion 
of most eminent philologists, aU human languages are not 
derived from a common primteval language, we must assume 
a polyphyletic origin of language, and in accordance with 
this a polyphyletic transition from speechless Ape-like Men 
to Genuine Men. 

( 295 ) 


ji; j;r ^ Boundary between the Invertebrate and Vertebrate Ancestors. 

Epochs of the 

History of the 

Geological Periodi 

of the 

Organic History 

oj tlie Earth. 

ATicestral Stages 

ITcarest Living 

Relatives of the 

Ancestral Stages. 






1. Laurcntian Period 

2. Cambrian Period 

3. Silurian Teriod 


(Compare p. K, and 
Plate XIV. and its 
explanat ion) 

4. Devonian Period 

5. Coal Period 




Epoch 6. Permian Period 





7. Trias Period 

8. Jura Period 

9. Chalk Period 





10. Eocene Period 

11. Miocene Period 

12. Pliocene Period 

'^- ( 13. Diluvial Period 

Qdaternakt j j^^ Alluvial Period 



1. Monera 

. Single-celled Pri- 
mseval aulmals 

. Many-celled Pri- 
maeval animals 

. Ciliated planulffi 

. Frimteval Intes- 
tinal animals 

B. Glidinff Worms 
< TuTbellarm) 

7. Soft-worma 

8. Sack worma 

9. Skull-less 

10. Sing;le-nostriled 
. (JtiQiiorrhi'na) 
\ 11. Frimseval fish 
^ iSdachii) 


Simple Amoebfe 

Communities of 



Planula lavvse 

Gastrula larvse 



? Between the Sea- 

squirta and Gliding 










'12. Salamander fish / 
(Dipn£uMa) *- 
I 13. Gilled Amphibia f 
I (^Sozobranchia] *■ 
14, Tailed Amphibia r 
i. (Sozura) 1^ 

Mud fish 



Axnlotl [Siredov) 



15. PriroffiVal Am- /'?BetweentheTailed- 
niota J Amphibia and Pri- 

(Protamnia) j mary mammals 

IG. Primary Ham- ^ ^c^kf._ti animals 
mala J 

( Promavima Ma) { 
17. Pouched animals f 
{Marsupialia) \ 


18. Semi-apes ( 
(^Prosi^ii<^) *■ 

19. Tailed Narrow- | 
nosed Apes ^- 

20. Men-like Apes 
Tail-lesa Narrow- 

nosed Apes 

21, Speechless Men or 

Ape-like Men 




Pouched rats . 

Lori (Stenops) 
Maki (Lemur) 
Nose aes 
Holy apes 
Gorilla, Chimpan- 
zee, Orang-, 
Deaf and Dumb, 
Cretins or Mici'O- 

i 22. Talking lUen •[ 

Australians and 




Ago of the Human Eace. — Causes of its Origin. — ^The Origin of Human 
Language. — Monoptyletic or Single, Polyphyletic or Multiple Origin of 
the Human Race. — Derivation of Man from many Pairs. — Classification 
of the Human Races. — System of Twelve Species of Men. — Woolly- 
Haired Men, or Ulotriohis. — Bushy -haired (Papuans, Hottentots). — 
Fleecy-haired (Caffres, Negroes). — Straight-haired men, or Lissotrichi. 
— Stiff-haired (Australians, Malays, Mongols, Arctic, and American 
Tribes). — Curly-haired (Dravidas, Nubians, Midlanders). — Number of 
Population. — Primaeval Home of Man (South Asia, or Lemuria). — 
Nature of Primaeval Men. — Number of Prima3val Languages (Monoglot- 
tists and Polyglottists) . — Divergence and Migration of the Human 
Eace.^GeograpMcal Distribution of the Human Species. 

The rich treasure of knowledge wc possess in the compara- 
tive anatomy and the history of the development of Verte- 
brate animals, enables us even now to establish the most 
important outlines of the human pedigree in the way we 
have done in the last chapter. One must, however, not 
expect to be able to survey satisfactorily in every detail 
the history or phylogeny of the human species which will 
henceforth form the basis of -Anthropology, and of all other 
sciences. The complete development of this most important 
science — of which we can only lay the first foundation — 
must remain reserved for the more accurate and extensive 


investigations of a future time. This applies also to those 
more special questions of human phylogeny at which it 
is desirable before concluding to take a cursory glance, 
namely, the question of the time and place of the origin of 
the human race, as also of the different species and races 
into which it has differentiated. 

In the first place, the period of the earth's history, within 
which the slow and gradual transmutation of the most 
man-like apes into the most ape-like men took place, can of 
course not be determined by years, nor even by centuries. 
This much can, however, with full assurance be maintained, 
for reasons given in the last chapter, that Man is derived 
from Placental animals. Now, as fossU remains of these 
Placentalia are fouiwd only in the tertiary rocks, the 
human race can at the earliest have developed only within 
the Tertiary period out of perfected man-like apes. What 
seems most probable is that this most important process in 
the history of terrestrial creation occurred towards the end 
of the Tertiary period, that is in the Pliocene, perhaps even 
in the Miocene period, but possibly also not until the 
beginning of the Diluvial period. At aU events Man, as 
such, lived in central Europe as early as the Diluvial period, 
contemporaneously with many large, long since extinct 
mammals, especially with the diluvial elephant, or mammoth 
(Elephas primigenius), the woolly -haired rhinoceros (Rhino- 
ceros tichorrhinus), the giant deer (Cervus euryceros), the 
cave bear (Ursus spelajus), the cave hysena (Hysena speltea). 
the cave lion (Felis spelseus), etc The results brought to 
light by recent geology and archssology as to these fossil 
men and their animal contemporaries of the diluvial period, 
are of the greatest interest. But as a closer' examination of 


them would occupy too mucli of my limited space, I m.ust 
confme myself here to setting forth their great general 
importance, and refer for particulars to the numerous 
writings which have recently been published on the 
Primseval History of Man, more especially to the excellent 
works of Charles LyeU^s" Carl Vogt,^? Friedrich Eolle,^^ 
J ohn Lubbock,** L. Biichner,** etc. 

The numerous and interesting discoveries presented to us 
by these extensive investigations of late years on the 
primaeval history of the human race, place the important 
fact (long since probable for many other reasons) beyond a 
doubt, that the human race, as such, has existed for more 
than twenty thousand years. But it is also probable that 
more than a liundi-ed thousand years, perhaps many 
hundred thousands of years, have elapsed since its first 
appearance; and, in contrast to this, it must seem very 
absurd that our calendars still represent the " Creation of 
the World, according to Calvisius," to have taken place 5821 
years ago. 

Now, whether we reckon the period during which the 
human race, as such, has existed and diffused itself over 
the earth, as twenty thousand, a hundred thousand, or 
many hundred thousands of years, the lapse of time is in 
any case immensely small in comparison with the in- 
conceivable length of time which was requisite for the 
gradual development of the long chain of human ancestors. 
This is evident even from the small thickness of all 
Diluvial deposits in comparison with the Tertiary, and of 
these again in comparison with the preceding deposits. 
(Compare p. 22.) But the infinitely long series of slowly 
and gradually developing animal forms from the simplest 


Moneron to the Ampliioxus, from this to the Primaeval Fish, 
from the PrimEeval Fish to the first Mammal, and ao'ain, 
from the latter to Man, also require for their historical 
development a succession of periods probably comprising 
many thousands of millions of years. (Compare vol. i. p. 129.) 

Those processes of development which led to the origin 
of the most Ape-like Men out of the most Man-like Apes 
must be looked for in the two adaptational changes which, 
above all others, are distinctive of Ma.n, namely, upright 
tvalk and articulate speech. These two physiological func- 
tions necessarily originated together with two corresponding 
morphological transmutations, with which they stand in the 
closest correlation, namely, the differentiation of the two 
fairs of limbs and the differentiation of tJie larynx. The 
important perfecting of these organs and their functions 
must have necessarily and powerfully reacted upon the 
differentiation of the brain and the mental activities de- 
pendent upon it, and thus have paved the way for the end- 
less career in which Man has since progressively developed, 
and in which he has far outstripped his animal ancestors, 
(Gen. Morph. ii. p. 430.) 

The first and earliest of these three great processes 
in the development of the human organism probably was 
the higher differentiation and the perfecting of the ex- 
tremities which was effected by the hahit of an upright 
tuallc. By the fore feet more and more exclusively adopt- 
ing and retaining the function of grasping and handling, 
and the hinder feet more and more exclusively the function 
of standing and walking, there was developed that contrast 
between the hand and foot which is indeed not exclusively 
characteristic of man, but which is much more strongly 


developed in hini than in the apes most like men. This 
differentiation of the fore and hinder extremities was, 
however, not merely most advantageous for their own 
develojjmeut and perfecting, but it was followed at the 
same time by a whole series of very important changes in 
other parts of the body. The whole vertebral column, and 
more especially the girdle of the pelvis and shoulders, 
as also the muscles belonging to them, thereby experienced 
those changes which distinguish the human body from 
that of the most man-like apes. These transmutations 
were probably accomplished long before the origin of 
articulate speech; and the human race thus existed for 
long, with an upright walk and the characteristic human 
form of body connected with it, before the actual develop- 
ment of human language, which would have completed the 
second and the more important part of human development. 
We may therefore distinguish a special (21st) stage in the 
series of our human ancestors, namely. Speechless Man 
(Alalus), or Ape-man (Pithecanthropus), whose body was 
indeed formed exactly like that of Man in all essential 
characteristics, but who did not as yet possess articulate 

The origin of articulate language, and the higJier differen- 
tiation and perfecting of the larynx connected with it, 
must be looked upon as only a later, and the most 
important stage in the process of the development of Man. 
It was, doubtless, this process which above all others 
helped to create the deep chasm between man and animal, 
and which also first caused the most important progress 
in the mental activity and the perfecting of the brain 
connected with it. There indeed exists in very many 


animals a language for communicating sensations, desires, 
and thoughts, partly a language of gestures, partly a 
language of feeling or touch, partly a language of cries 
or sounds, but a real language of words or ideas, a so-caUed 
"articulate" language, which by abstraction changes sounds 
into words, and words into sentences, belongs, as far as we 
know, exclusively to Man. 

The origin of human language must, more than anything 
else, have had an ennobling and transformiug influence 
upon the mental life of Man, and consequently upon his 
brain. The higher differentiation and perfecting of the 
brain and mental life as its highest function developed in 
direct coiTclation with its expression by means of speech. 
Hence, the highest authorities in comparative philology 
justly see in the development of human speech the most 
important process which distinguishes Man from his animal 
ancestors. This has been especially set forth by August 
Schleicher, in his treatise "On the Importance of Speech 
for the Natural History of Man." ^ In this relation we see 
one of the closest connections between comparative zoology 
and comparative philology; and here the theory of develop- 
ment assigns to the latter the task of foUowuig the origin 
of language step by step. This task, as interesting as it is 
important, has of late years been successfully undertaken by 
many inquirers, but more especially by Wilhehn Bleek, who 
has been occupied for seventeen years in South Africa with 
the study of the languages of the lowest races of men, and 
hence has been enabled to solve the question. August 
Schleicher more especially discusses, in accordance with the 
theory of selection, how the various forms of speech, like 
aU other organic forms and functions, have developed by 


the process of natural selection, and have divided into 
many species and dialects. 

I have no space here to follow the process of the forma- 
tion of language, and must refer in regard to this to the 
above-mentioned important work of Wilhelm Bleek, " On 
the Origin of Language." ^^ But we have stiU to mention 
one of the most important results of comparative philology, 
which is of the highest importance to the genealogy of the 
human species, that is, that human language was probably 
of a tnultiple, or polyphyletic origin. Human speech, as 
such, did not develop probably until the genus of Speech- 
less or Primasval Man, or Ape Man, had separated into several 
kinds or species. In each of these human species, and 
perhaps even in the different sub-species and varieties of 
this species, language developed freely and independently 
of the others. ' At least Schleicher, one of the first 
authorities on the subject, maintains that " even the 
besfinninjis of language — in sounds as weU as in regard to 
ideas and views which were reflected in sounds, and further, 
in regard to their capability of development — must have 
been different. For it is positively impossible to trace aU 
languages to one and the same primaeval language. An 
impartial investigation rather shows that there are as many 
primjeval languages as there are races." ^* In like manner, 
Friederich Miiller*'- and other eminent linguists assume a 
free and independent origin of the families of languages 
and their primaeval stocks. It is well known, however, 
that the boundaries of these tribes of languages and their 
ramifications are by no means always the boundaries 
of the different human species, or the so-called "races," 
distinguished by us on account of their bodily character- 


istics. This, as well as the complicated relations of the 
mixture of races, and the various forms of hybrids, is 
the great difficulty lying in the way of tracing the 
human pedigree in its individual branches, species, races, 
varieties, etc. 

In spite of these great and serious difficulties, we cannot 
here refrain from taking one more cursory glance at the 
ramification of the human pedigree, and at the same time 
considering, from the point of view of the theory of descent, 
the much discussed question of the monophyletic or poly- 
phyletic origin of the human race, and its species or races. 
As is well known, two great parties have for a long time 
been at war with each other upon this question; the 
monophylists (or monogenists) maintain the unity of origin 
and the blood relationship of all races of men. The poly- 
phylists (or polygenists), on the other hand, are of opinion 
that the different races of men are of independent origin. 
According to our previous genealogical investigations we 
cannot doubt that, at least in a wide sense, the monophy- 
letic opinion is the right one. For even supposing that the 
transmutation of Man-like Apes into Men had taken place 
several tiraes, yet those Apes themselves would again be 
allied by the one pedigree common to the whole order of 
Apes. The question therefore would always be merely 
about a nearer or remoter degree of blood relationship. In 
a narrmuer sense, on the other hand, the polyphylist's 
opinion would probably be right, inasmuch as the different 
primaeval languages have developed quite independently of 
one another. Hence, if the origin of an articulate language 
is considered as the real and principal act of humanification, 
and the species of the human race are distinguished accord- 


ing to the roots of their language, it might be said that the 
different races of men had originated, independently of one 
another, by diiferent branches of primosval, speechless men 
directly springing from apes, and forming their own pri- 
maeval language. StUl they would of course be connected 
further up or lower down at their root, and thus aU would 
finally be derived from a common prima3val stock. 

While we hold the latter of these convictions, and while 
we for many reasons believe that the different species of 
speechless prim^ffival men were all derived from a common 
ape like human form, we do not of course mean to say 
that all men are descended frorn, one pair. This latter 
supposition, which our modern Indo-Germanic culture has 
taken from the Semitic myth of the Mosaic history of 
creation, is by no means tenable. The whole of the 
celebrated dispute, as to whether the human race is descended 
from a single pair or not, rests upon a completely false way 
of putting the question. It is just as senseless as the 
dispute as to whether all sporting dogs or all race-horses 
are descended from a single pair. We might with equal 
justice ask whether all Germans or all Englishnien are 
" descended from a single pair," etc. A " first human pair," 
or " a first man," has in fact never existed, any more than 
there ever existed a first pair or a first individual of 
Englishmen, Germans, race-horses, or sporting dogs. The 
origin of a new species, of course, always results from an 
existing species, by a long chain of many different indi- 
viduals sharing the slow process of transformation. 
Supposing that we had all the different pairs of Human 
Apes and Ape-like Men before us — which belong to the trjie 
ancestors of the human race — it would oven then be quite 


impossible (without doing so most arbitrarily) to call any- 
one of these pairs of ape-like men "the first pair." As 
little can we derive each of the twelve races or species 
of men, which we shall consider directly, from a "first pair." 
The difficulties met with in classifying the different 
races or species of men are quite the same as those 
which we discover in classifying animal and vegetable, 
species. In both cases forms apparently quite different 
are connected with one another by a chain of inter- 
mediate forms of transition. In both cases the dispute as to 
what is a kind or a species, what a race or a variety, can 
never be determined. Since Blumenbach's time, as is well 
known, it has been thought that mankind may be divided 
into five races or varieties, namely : (1) the Ethiopian, or 
black race (African negro) ; (2) the Malayan, or brown race 
(Malays, Polynesians, and Australians) ; (3) the Mongolian, 
or yellow race (the principal inhabitants of Asia and the 
Esquimaux of North America) ; (4) the Americans, or red race 
(the aborigines of America) ; and (5) the Caucasian, or white 
race (Europeans, north Africans, and south-western Asiatics). 
All of these five races of men, according to the Jewish legend 
of creation, are said to have been descended from "a, single 
pair " — Adam and Eve, — and in accordance with this are said 
to be varieties of one kind or species. If, however, we com- 
pare them without prejudice, there can be no doubt that the 
differences of these five races are as great and even greater 
than the " specific differences " by which zoologists and 
botanists distinguish recognised "good" animal and vege- 
table species (" bonae species "). The excellent palseontologist 
Quenstedt is right in maintaining that, "if Negroes and 
Caucasians were snails, zoologists would universally agree 


tliat they represented two very excellent species, which 
could never have originated from one pair by gradual 

The characteristics by which the races of men are 
gradually distinguished are partly taken from the formation 
of the hair, partly from the colour of the skin, and partly 
from the formation of the skull. In regard to the last cha- 
racter, two extremes are distinguished, namely, long heads 
and short heads. In long-headed men (Dolichoeephali) 
whose strongest development is foimd in Negroes and 
Australians, the skull is extended, nai'row, and compressed 
on the right and left. In short-headed men (Brachycephali), 
on the other hand, the skull is compressed in an exactly 
opposite manner, from the front to the back, is short and 
broad, which is especially striking in the case of the 
Mongolians. Medium-headed men (Mesocephali), standino- 
between the two extremes, predominate especially among 
Americans. In every one of these three groups we find 
men with slanting teeth (Prognathi), whose jaws, like those 
of the animal snout, strongly project, and whose front teeth 
therefore slope in front, and men with straight teeth 
(Orthognathi), whose jaws project but little, and whose front 
teeth stand perpendicularly. During the last ten years a 
great deal of time and trouble have been devoted to the 
careful examination and measurement of the forms of skulls 
which have, however, not been rewarded by correspondino- 
results. For within a single species, as for example within 
the Mediterranean species, the form of the skull may vary 
so much that both extremes are met with in the same 
species. Much better starting-points for the classification of 
of the human species are furnished by the nature of the 


hair and speeeli, because ttey are mucli more strictly 
hereditary than the form of the skulL 

Comparative philology seems especially to be becoming 
an authority in this matter. In the latest great work 
on the races of men, which Friederich Miiller has pub- 
lished in his excellent "Ethnography,"^ he justly places 
language in the fore-ground. Next to it the nature of 
the hair of the head is of great importance ; for although it 
is in itself of course only a subordinate morphological ' 
character, yet it seems to be strictly transmitted within 
the race. Of the twelve species of men distinguished on 
the following table (p. 308), the four lower species are 
characterised by the woolly nature of the hair of their 
heads; every hair is flattened like a tape, and thus its 
section is ovaL These four species of woolly-haired Tnen 
(Ulotrichi) we may reduce into two groups — tuft-haired' 
and fleecy-haired. The hair on the head of tuft-haired 
men (Lophocomi), Papuans and Hottentots, gi-ows in 
unequally divided small tufts. The woolly hair of fleecy- 
haired men (Eriocomi), on the other hand, in Caffres and 
Negroes, grows equally all over the skin of the head. All 
Ulotrichi, or woolly-haired men, have slanting teeth and long 
heads, and the colour of their skin, hair, and eyes is always 
very dark. All are inhabitants of the Southern Hemi- 
sphere; it is only in Africa that they come north of the 
equator. They are on the whole at a much lower stage of 
development, and more like apes, than most of the 
Lissotrichi, or straight-haired men. The Ulotrichi are 
incapable of a true inner culture and of a higher mental 
development, even under the favourable conditions of 
adaptation now offered to them in the United States of 




Of the 12 Species of Men and their 36 Races. 
(Compare Plate XV.) 




from the 

1. Papuan 
Homo Fapua 

2. Jtjottcntnt 


3. ©aEfrc 
Homo Cafer 

4. licgto 
Homo Niger 

1. Nigritoa 




New Guinea men 
Zulu Kaffrea 
Congo Kaffrea 
Tibu negroes 
Soudan negroes 

Malacca, Philippine 

New Guinea 
"Van DIemen's Land 
The Cape 
The Cape 

Eastern South Africa 
Central South Africa 
Western South Africa 
Tibn district 














5. australian ( 14. 
H. Australia * 15. 


6. fHaan 17. 
HomoKalayus ) 18. 

North Australians North Australia 
South Australians South Australia 

7. fHnnfsotan 



8. Stctit Sacn ) 
Homo Arcticas ( 

9. amctican 





Natives of Mada- 
Coreo- Japanese 
Altaians 1 
Utralians f 


North Americans 

Sunda Archipelago 
Paoifi-O Arohipelajjo 


Tibet, China 

Corea, Japan 

Central Asia, North Asia 

North-western Asia, 

Northern Europe, 

Extreme N.E. of Asia 
The extreme north of 

North America 







Central Americans Central America 
South Americans South America 

10. SrabiUas j 29. 
H. Dravida ( 30. 

11. laubian /3i- 
Homo Nuba (_ ^' 









The extreme south of 
South America 




Euln-land (Central 


Extreme north of Spain 

Arabia,North Africa,etc. 

South-westrm Asia, 
Em-ope, etc. 




North ? 


South ? 



y. Americans 



8. arctic Mtn 








aitaians fflttalians 


12. fHeSttcttanese 

10. Srabi»as 



11. liuiiians 





Sajianrsc luBos 

7. Manuals 



6. iMalaas 

4. llFgrocs 
3. Batftcs 


^romaligs 2. |t!Dttcntots 

1. ^Qapuans 
5. Australians I 





FrimaBval Men 


North America. No ■woolly-haired nation has ever had an 
important " history." 

In the eight higher races of men, whicli we comprise as 
straight-haired (Lissotrichi), the hair of the head is never 
actually vs'oolly, although it is very much frizzled in some 
individuals. Every separate hair is cylindrical (not like a 
tap)e), and hence its section is circular (not oval). 

The eight races of Lissotrichi may likewise be divided 
into two groups — stiff-haired and curly -haired. Stiff-haired 
men (Euthycomi), the hair of whose heads is quite smooth 
and straight, and not frizzled, include Australians, Malays, 
Mongolians, Arctic tribes, and Americans. Curly-haired 
men, on the other hand, the hair of whose heads is more or 
less curly, and in whom the beard is more developed than 
in all other species, include the Dravidas, Nubians, and 
Mediterranean races. (Compare Plate XV.) 

Now, before we venture upon the attempt hypothetically 
to explain the phyletic divergence of mankind, and the 
genealogical connection of its different species, we will 
premise a short description of the twelve named species 
and of their distribution. In order clearly to survey their 
geographical distribution, we must go back some three or 
four centuries, to the time when the Indian Islands and 
America were first discovered, and when the present great 
mingluig of species, and more especially the influx of the 
Indo-Germanic race, had as yet not made great progress. 
We begin with the lowest stages, with the woolly-haired 
men (Ulotrichi), all of whom are prognathic Dolicho- 

The Papuan (Homo Papua), of all the still living human 
species, is perhaps most closely related to the original primary 


form of woolly-liaired men. This species now inhabits 
only the large island of New Guinea and the Archipelago 
of Melanesia lying to the east of it (Solomon's Islands, New 
Caledonia, the New Hebrides, etc.). But scattered remnants 
of it are also still found in the interior of the peninsula 
of Malacca, and likewise in many other islands of the large 
Pacific Archipelago ; mostly in the inaccessible mountainous 
parts of the interior, and especially in the Philippine 
Islands. The but lately extinct Tasmanians, or the natives 
of Van Diemen's Land, belonged to this group. From these 
and other circumstances it is clear that the Papuans in former 
times possessed a much larger area of distribution in south- 
eastern Asia. They were driven out by the Malays and 
forced eastwards. The skin of all Papuans is of a black 
colour, sometimes more inclining to brown, sometimes more 
to blue. Their woolly hair grows in tufts, is spirally twisted 
in screws, and often more than a foot in length, so that it 
forms a strong ^vooUy wig, which stands far out from^ the 
head. Their face, below the narrow depressed forehead, has 
a large turned-up nose and thick protruding lips. The 
peculiar form of their hair and speech so essentially dis- 
tinguishes the Papuans from their straight-haired neighbours, 
from the Malays as well as from the Australians, that they 
must be regarded as an entu-ely distinct species. 

Closely related to the Papuans by the tufted growth of 
hair, but geographically widely separated from them, are 
the Hottentots (Homo Hottentottus). They inhabit exclu- 
sively the southernmost part of Africa, the Cape and the 
adjacent parts, and have immigrated there from the north- 
east. The Hottentots, like their original kinsmen the Pa- 
puans, occupied in former times a much larger area (prob- 


ably the whole of Eastern Africa), and are now approach- 
ing their extinction. Besides the genuine Hottentots — of 
whom there now exist only the two tribes of the Coraca (in 
the eastern Cape districts) and the Namaca (in the western 
portion of the Cape) — this species also includes the Bush- 
men (in the mountainous interior of the Cape). The woolly 
hair of all Hottentots grows in tufts, like brushes, as in the 
case of Papuans. Both species also agree in the posterior 
part of the body, in the female sex being specially inclined 
to form a great accumulation of fat (Steatopygia). But the 
skin of Hottentots is much lighter, of a yellowish brown 
colour. Their very flat face is remarkable for its small fore- 
head and nose, and large nostrils. The mouth is very broad 
with big lips, the chin small and pointed. Their speech is 
characterised by several quite peculiar guttural sounds. 

The next neighbours and kinsmen of Hottentots are 
Kaffres (Homo Cafer). This woolly-haired human species 
is, however, distinguished, like the following one (the 
genuine Negro), from Hottentots and Papuans by the woolly 
hair not being divided into tufts, but covering the head as a 
thick fleece. The colour of their skin varies through all shades, 
from the yellowish black of the Hottentot to the brown 
black or pure black of the genuine Negro. While in former 
times the ]-ace of Kaffres was assigned to a very small area 
of distribution, and was generally looked upon only as a 
variety of the genuine Negro, this species is now considered 
to include almost the whole of the inhabitants of equatorial 
Africa, from the 20th degree south latitude to the 4th 
degree north ; consequently, all South Africans, with the 
exception of the Hottentots. They include especially the 
inhabitants of the Zulu, Zambesi, and Mozambique districts 


on the east coast, the large human families of the Besehuans 
or Setschuans in the interior, and the HeiTero and Cono-o 
tribes of the west coast. They too, like the Hottentots, 
have immigrated from the north-east. Kaffres, who were 
usually classed with Negroes, differ very essentially from 
them by the formation of their skull and by their speech. 
Their face is long and narrow, their forehead high, and their 
nose prominent and frequently curved, their lips not so pro- 
truding, and their chin pointed. The many languages of 
the different tribes of Kaffres can all be derived from an 
extinct primaeval language, namely, from the" Bantu lan- 

The genuine Kegro (Homo Niger) — when Kaffres, Hot- 
tentots, and Nubians are separated from him — at present 
forms a much less comprehensive human species than was 
formerly supposed. They now only include the Tibus, in 
the eastern parts of the Sahara ; the Sudan people, or 
Sudians, who inhabit the south of that large desert ; also 
the inhabitants of the Western Coast of Africa, from the 
mouth of the Senegal in the north, to beyond the estuary 
of the Niger in the south (Senegambians and Nigritians). 
Genuine Negroes arc accordingly confined between the 
equator and the Tropic of Capricorn, and only a small por- 
tion of the Tibu tribe in the east have gone beyond this 
boundary. The Negro species has spread within this zone, 
coming from the east. The colour of the skin of genuine 
negroes is always more or less of a pure black. Their 
skin is velvety to the touch, and characterised by a 
peculiar offensive e:vhalation.. Although Negroes agi'ee with 
Kaffres in the formation of the woolly hair of the head, 
yet they differ essentially in the formation of their face. 


Their forehead is flatter and lower, their nose broad and 
thick, not prominent, their lips large and protruding, and 
their chin very short. Genuine Negroes are moreover dis- 
tinguished by very thin calves and very long arms. This 
species of men must have branched into many separate 
tribes at a very early period, for their numerous and 
entirely distinct languages can in no way be traced to one 
primaeval language. 

To the four woolly-haired species of men just discussed, 
straight-haired men (Homines Lissotrichi) stand in strong 
contrast, as another main branch of the genus. Five of the 
eight species of the latter^ as we have seen, can be com- 
prised as stiff-haired (Euthycomi) and three as curly-haired 
(Euplocomi). We shall in the fii'st place consider the 
former, which includes the primaeval inhabitants of the 
greater part of Asia and the whole of America. 

The lowest stage of all straight-haired men, and on the 
whole perhaps of all the still living human species, is occu- 
pied by the Australian, or Austrcd-negro (Homo Australis). 
This species seems to be exclusively confined to the large 
island of Australia ; it resembles the genuine African Negro 
by its black or brownish black hair, and the offensive smeU. 
of the skin, by its very slanting teeth and long-headed form 
of skull, the receding forehead, broad nose, protruding lips, 
and also by tlie entire absence of calves. On the other hand 
Australians differ .from genuine Negroes as well as from 
their nearest neighbours the Papuans, by the much weaker 
and more delicate structure of then- bones, and more 
esj^ecially by the formation of the hair of their heads, which 
is not woolly and frizzled, but either quite lank or only 
slightly curled. The veiy low stage of bodily and mental 


development of the Australian is perhaps not altogether 
original, but has arisen by degeneration, that is, by adapta- 
tion to the very unfavourable conditions of existence in 
Australia. They probably immigrated to their present 
home from the north or north-west, as a very early off- 
shoot of the Euthycomi. They are probably more closely 
related to the Dravidas, and hence to the Euplocomi, than 
the other Euthycomi. The very peculiar language of the 
Australians is broken up into numerous small branches, 
which are grouped into a northern and a southern class. 

The Malay (nemo Malayus), the brown race of ethnogra- 
phers, although not a large species, is important in regard 
to its genealogy. An extinct south Asiatic human species, 
very closely related to the Malays of the present day, must 
probably be looked upon as the common primary form of 
this and the following higher human species. We will 
call this hypothetical primary species, Primssval Malays, or 
Promalays. The Malays of the present day are divided 
into two widely dispersed races, the Sundanesians, who 
inhabit Malacca, the Sunda Islands (Sumatra, Java, Borneo, 
etc.) and the Philippine Islands, and the Polynesians, who 
are dispersed over the greater portion of the Pacific Archi- 
pelago. The northern boundary of their wide tract of 
distribution is formed on the east by the Sandwich Islands 
(Hawai), and on the west by the Marian Islands (Ladrones) ; 
the southern boundary on the east is formed by the Man- 
gareva Archipelago, and on the west by New Zealand. The 
inhabitants of Madagascar are an especial branch of Sunda- 
nesians who have been driven to the far west. This wide 
pelagic distribution of the Malays is explained by their 
partiality for nautical life. Their primasval home is the 


south-eastern portion of the Asiatic continent, from whence 
they spread to the east and south, and drove the 
Papuans before them. The Malays, in the formation of 
body, are nearest akin to the Mongols, but are also 
nearly allied to the curly-haired Mediterranese. They are 
generally short-headed, more rarely medium-headed, and 
very rarely long-headed. Their hair is black and stiff, but 
frequently somevsrhat curled. The colour of their skin is 
brown, sometimes yellowish, or of a cinnamon colour, some- 
times reddish or copper brown, more rarely dark brown. 
In regard to the formation of face, Malays in a great 
measure form an intermediate stage between the Mongols 
and the Mediterranese ; they can frequently not be distin- 
guished from the latter. Their face is generally broad, with 
prominent nose and thick lips, the opening for their eyes 
not so narrowly cut and slanting as in Mongols. The near 
relationship between all Malays and Poljaiesians is proved 
by their language, which indeed broke up at an early 
period into many small branches, but still can always be 
traced to a common and quite peculiar primaeval language. 

The Mongol (Homo Mongolus) is, next to the Mediter- 
ranese, the richest in individuals. Among them are all the 
inhabitants of the Asiatic Continent, excepting the Hjrper- 
boreans in the north, the few Malays in the south-east 
(Malacca), the Dravidas in Western India^, and the Mediter- 
ranese in the south-west. In Europe this species of men 
is represented by the Fins and Lapps in the north, by the 
Osmanlis in Turkey, and the Magyars in Hungary. The 
colour of the Mongol is always distinguished by a yellow 
tone, sometimes a light pea green, or even Avhite, some- 
times a darker brownish yellow. Their hair is always 


stiff and black. The form of their skull is, in the great 
majority of cases, decidedly short (especially in Kalmucks, 
Baschkirs, etc.) but frequently of medium length (Tartars, 
Chinese, etc.) But among them we never meet with genuine 
long-headed men. The narrow openings of their eyes, 
which are generally slanting, their prominent cheek bones, 
broad noses, and thick lips are very striking' as well as the 
round form of their faces. The language of the Mongols is 
probably traceable to a common primaeval language ; but 
the monosyllabic languages of the Indo-Chinese races, and 
the polysyllabic languages of the other Mongol races, stand 
in contrast as two main branches which separated at an 
early time. The monosyllabic tribes of the Indo-Chinese 
include the Tibetans, Birmans, Siamese, and Chinese. The 
other polysyllabic Mongols are divided into three races, 
namely: (1) the Coreo- Japanese (Coreansand Japanese); (2) 
the Altaians (Tartars, Kirgises, Kalmucks, Buriats, Tungu- 
sians) ; and (3) the Uralians (Samoiedes, Fins). The 
Magyars of Hungary are descended from the Fins. 

The Polar men (Homo Ai-cticus) must be looked upon as 
a branch of the Mongolian human species. We comprise 
under this name the inhabitants of the Arctic Polar lands 
of both hemispheres, the Esquimaux (and Greenlanders) in 
North America, and the Hyperboreans in north-eastern 
Asia (Jukagirs, Tschuksches, Kuriaks, and Kamtschads.) 
By adaptation to the Polar climate, this human race has 
become so peculiarly transformed that it may be considered 
as a distinct species. Their stature is low and of a square 
build ; the formation of their skull of medium size or even 
long; their eyes narrow and slanting like the Mongols; 
their cheek-bones prominent, and their mouth wide. Their 



hair is stiff and black ; the colour of their skin is of a 
light or dark brown tinge, sometimes" more inclined to 
white or to yellow, like that of the Mongols, sometimes 
more to red, like that of the Americans. The languages of 
Polar men are as yet little known, but they differ both 
from the Mongolian and from the American. Polar men 
must probably be regarded as a remnant and a peculiarly 
adapted branch of that tribe of Mongols which emigrated 
from north-eastern Asia to North America, and populated 
that part of the earth. 

At the time of the discovery of America, that part of 
the earth was peopled (setting aside the Esquimaux) only 
by a single human species, namely, by the Redskins, or 
Americans (Homo Americanus). Of all other human spe- 
cies they are most closely related to the two preceding. 
The form of their skull is generally a medium one, rarely 
short or long-headed. Their forehead broad and very low; 
their nose large, prominent, and frequently aquiline ; their 
cheek-bones f)rominent; their lips rather thin than thick. 
The colour of their skin is characterised by a red funda- 
mental tint, which is, however, sometimes pure copper- 
red, or light red, sometimes a deeper reddish brown, yellow 
brown or olive brown. The numerous languages of the 
various American races and tribes are extremely different, 
yet they agree in their original foundation. Probably 
America was first peopled from north-eastern Asia by 
the same tribe of Mongols from whom the Polar men 
(Hyperboreans and Esquimaux) have also branched. This 
tribe fii-st spread in North America, and from thence 
migrated over the isthmus of Central America down to 
South America, at the extreme south of which the species 


degenerated very mucli by adaptation to the very un- 
favourable conditions of existence. But it is also possible 
that Mongols and Polynesians immigTated from the west 
and mixed with the former tribe. In any case the 
aborigines of America came over from the Old World, and 
did not, as some suppose, in any way originate out of 
American apes. Catarrhini, or Narrow-nosed Apes, never 
at any period existed in America. 

The three human species still to be considered — the 
Dravidas, Nubians, and Mediterranese — agree in several 
characteristics which seem to establish a close relationship 
between them, and distinguish them from the preceding 
species. The chief of these characteristics is the strong 
development of the beard, which in all other Sf)eeies is 
either entirely wanting or but very scanty. The hair of 
their heads is generally not so lank and smooth as in the 
five preceding species, but in most cases more or less curly. 
Other characteristics also seem to favour our classing them 
in one main group of curly-haired men (Euplocomi). 

The Bravida man (Homo Dravida) seems to stand very 
near the common primary form of the Euplocomi, and 
perhaps of Lissotrichi. At present this primaeval species 
is only represented by the Deccan tribes in the southern 
part of Hind(?^tan, and by the neighbouring inhabitants of 
the mountains on the north-east of Ceylon. But in earlier 
times this race seems to have occupied the whole of 
Hindostan, and to have spread even further. It shows, on 
the one hand, traits of relationship to the Australians and 
Malays ; on the other, to the Mongols and Mediterranese. 
Their skin is either of a light or dark brown colour; in 
some tribes, of a yellowish brown, in others, almost black 


brown. The hair of their heads, as in Mediterranese, is 
more or less curled, neither quite smooth, like that of the 
Euthycomi, nor actually woolly, like that of the Ulotrichi. 
The strong development of the beard is also like that of the 
Mediterranese. The oval form of face seems partly to be akin 
to that of the Malays, partly to that of the MediteiTanese. 
Their forehead is generally high, their nose prominent and 
narrow, their lips slightly protruding. Their language is 
now very much mixed with Indo- Germanic elements, but 
seems to have been originally derived from a very peculiar 
primEBval language. 

The Kuhian (Homo Nuba) has caused ethnographers no 
fewer difficulties than the Dravida species, ^j this name 
we understand not merely the real Nubians (Schangallas, or 
Dongolese), but also their near kinsmen, the Fulas, or 
Fellatas. The real Nubians inhabit the countries of the 
Upper Nile (Dongola, Schangalla, Barabra, Cordofan) ; the 
Fulas, or Fellatas, on the other hand, have thence migrated 
far westward, and now inhabit a broad tract in the south of 
the western Sahara, hemmed in between the Soudanians in 
the north and the Nigritos in the south. The Nubian and 
Fula races are generally either classed with negroes or with 
the Hamitic races (thus with Mediterranese), but are so 
essentially different from both that they muft be regarded 
as a distinct species. In former times they very probably 
occupied a large part of north-eastern Africa. The skin of 
the Nubian and Fula races is of a yellowish or reddish 
brown colour, more rarely dark brown or approaching to 
black. Their hair is not woolly but curled, frequently even 
quite smooth ; its colour is dark brown or black. Their 
beard is much more strongly developed than in negroes. 


The oval formation of their faces approaches more to the 
Mediterranean than to the Negro type. Their forehead is 
high and broad, their nose prominent and not flat, their lips 
not so protruding as in the negro. The language of the 
Nubian races seems to possess no relationship to those of 
genuine negroes. 

The Caucasian, or Mediterranean man (Homo Mediterra- 
neus), has from time immemorial been placed at the head of 
all races of men, as the most highly developed and perfect. 
It is generally called the Caucasian race, but as among all 
the varieties of the species, the Caucasian branch is the least 
important, we prefer the much more suitable appellation 
proposed by Friedrich Miiller, namely, that of Mediterra- 
nean, or Midland men. For the most important varieties of 
this species, which are moreover the most eminent actors in 
what is caUed " Universal History," first rose to a flourishing 
condition on the shores of the Mediterranean The former 
area of the distribution of this species is expressed by the 
name of " Indo- Atlantic" species, whereas at present it is 
spread over the whole earth, and is overcoming most of the 
other species in the struggle for existence. In bodily as 
weU as in mental qualities, no other human species can 
equal the Mediterranean. This species alone (with the 
exception of the Mongolian) has had an actual history ; 
it alone has attained to that degree of civilization which 
seems to raise man above the rest of nature. 

The characteristics which distinguish the Mediterranean 
from the other species of the race are well known. The 
chief of the external features is the light colour of the skin, 
which however exhibits all shades, from pure white or 
reddish white, through yellow or yellowish bro^vn to dark 


brown or even black brown. The growtli of the hair is 
generally strong, the hair of the head more or less curly, the 
hair of the beard stronger than in any of the other species. 
The foiTQ of the skull shows a great development in breadth ; 
medium heads predominate upon the whole, but long'and 
short heads are also widely distributed. It is only in this 
one species of men that the body as a whole attains that 
symmetry in all parts, and that equal development, which 
we call the type of perfect human beauty. The languages 
of all the races of this species can by no means be traced 
to a single common prima3val language ; we must at least 
assume four radically different primaeval languages. In 
accordance with this we must also assume within this one 
species four different races, which are only connected at 
their root. Two of these races, the Basques and Caucasians, 
now exist only as small remnants. The Basques, which in 
earlier times peopled the whole of Spain and the south of 
France, now inhabit but a narrow tract of land on the 
northern coast of Spain, on the Bay of Biscay. The remnant 
of the Caucasian race (the Daghestans, Tschercassians, 
Mingrclians, and Georgians) are now confined to the districts 
of Mount Caucasus. The language of the Caucasians as 
well as that of the Basques is entirely peculiar, and can be 
traced neither to the Semitic nor to the Indo-Germanic 
primaeval languages. 

Even the languages of the two principal races of the 
Mediterranean species — the Semitic and Indo-Germanic — 
cannot be traced to a common origin, and consequently these 
two races must have separated at a very early period. 
Semites and Indo-Germani are descended from different 
ape-like men. The Semitic race likewise separated at a 


very early period into two diverging branches, namely, into 
the Egyptian and Arabic branches. The Egyptian, or 
African branch, the Byssemites — which sometimes under 
the name of Hamites are entirely separated from the Semites 
• — embraces the large group of Berbers, who occupy the 
whole of north Africa, and in earlier times also peopled 
the Canary Islands, and, finally, also the group of the 
Ethiopians, the Bedsha, Galla, Danakil, Somali, and 
other tribes which occupy all the north-eastern shores of 
Africa as far as the equator. The Arabic, or Asiatic branch, 
that is, the Eusemites, also called Semites in a narrow sense, 
embrace the inhabitants of the large Arabian peninsula, 
the primseval family of genuine Arabians ("primeval type 
of the Semites"), and also the most highly developed Semi- 
tic groups, the Jews, or Hebrews, and the Aramaeans — the 
Syrians and Chaldseans. A colony of the southern Arabs 
(the Himjarites), which crossed the Straits of Bab-el-Mandeb, 
has peopled Abyssinia. 

Lastly, the Indo-Germanic race, which has far surpassed 
all the other races of men in mental development, sepa- 
rated at a very early period, like the Semitic, into two 
diverging branches, the Ario-liomaic and the Slavo- 
Germanic branches. Out of the former arose on the one 
hand the Arians (Indians and Iranians), on the other the 
Grceco-Roman (Greeks and Albanians, Italians and Kelts). 
Out of the Slavo-Germanic branch were developed on the 
one hand the Slavonians (Russian, Bulgarian, Tehee, and 
Baltic tribes), on the other the Germani (Scandinavians 
and Germans, Netherlanders and Anglo-Saxons). August 
Schleicher has explained, in a very clear genealogical form, 
how the further ramifications of the Indo-Germanic race may 


be accurately traced in detail on the basis of comparative 
phUology.® (Compare p. 331.) 

The total number of human individuals at present 
amounts to between 1,300 and 1,400 millions. In our 
Tabular Survey (p. 333) 1,350 millions has been assumed as 
the mean number. According to an approximate estimate, 
as far as such a thing is possible, 1,200 millions of these are 
straight-haired men, only about 150 millions woolly-haired. 
The most highly developed species, Mongols and Mediterra- 
nese, far surpass all the other human species in numbers of 
individuals, for each of them alone comprises about 650 
millions. (Compare Frlederlch Miiller's Ethnography, p. 30.) 
Of course the relative number of the twelve species fluc- 
tuates every year, and that too according to the law 
developed by Darwin, that in the struggle for life the more 
highly developed, the more favoured and larger gi'oups 
of forms, possess the positive inclination and the certain 
tendency to spread more and more at the expense of 
the lower, more backward, and smaller groups. Thus the 
Mediterranean species, and within it the Indo-Germanic, 
have by means of the higher development of their brain 
surpassed all the other races and species in the struggle 
for life, and have ah-eady spread the net of their dominion 
over the whole globe. It is only the Mongolian species 
which can at aU successfully, at least in certain respects, 
compete with the Mediterranean, Within the tropical 
regions, Negroes, Kaffres, and Nubians, as also the Malays 
and Dravidas, are in some measure protected against the 
encroachments of the Indo-Germanic tribes by their beino- 
better adapted for a hot climate ; the case of the arctic 
tribes of the polar regions is similar. But the other races. 


which as it is are very much diminished ia number, -will 
sooner or later completely succumb in the struggle for 
existence to the superiority of the Mediterranean races. 
The American and Australian tribes are even now fast 
approaching their complete extinction, and the same may 
be said of the Papuans and Hottentots. 

In now turning to the equally interesting and difficult 
question of the relative connection, migration, and primceval 
home of the twelve species of men, I must premise the 
remark that, in the present state of our anthropological 
knowledge, any answer to this question must be regarded 
only as a provisional hypothesis. This is much the same as 
with any genealogical hypothesis which we may form of 
the origin of kindred animal and vegetable species, on the 
basis of the "Natural System." But the necessary un- 
certainty of these special hypotheses of descent, in no way 
shakes the absolute certainty of the general theory of 
descent. Man, we may feel certain, is descended from 
Catarrhini, or narrow-nosed apes, whether we agree with 
the polyphylites, and suppose each human species, in its 
primeval home, to have originated out of a special kind of 
ape ; or whether, agi-eeing with the monophylites, we suppose 
that all the human species arose only by differentiation from 
a single species of primaeval man (Homo primigenius). 

For many and weighty reasons we hold the monophyletic 
hypothesis to be the more correct, and we therefore assume 
a single primxsval Iwrne for mankind, where he developed 
out of a long since extinct anthropoid species of ape. Of 
the five now existing continents, neither Australia, nor 
America, nor Europe can have been this primreval home, 
or the so-called " Paradise," the " cradle of the human race." 


Most circumstances indicate southern Asia as the locality in 
question. Besides southern Asia, the only other of the now 
existing continents which might be viewed in this light is 
Africa. But there are a number of circumstances (especially 
chorological facts) which suggest that the primeval home 
of man was a continent now sunk below the surface of the 
Indian Ocean, which extended along the south of Asia, as it 
is at present (and probably in direct connection with it), 
towards the east, as far as further India and the Sunda 
Islands ; towards the west, as far as Madagascar and the 
south-eastern shores of Africa. We have already mentioned 
that many facts in animal and vegetable geography render 
the former existence of such a south Indian continent very 
probable. (Compare vol. i. p. 361.) Sclater has given this 
continent the name of Lemuria, from the Semi-apes which 
were characteristic of it. By assuming this Lemuria to 
have been man's primseval home, we gi-eatly facilitate the 
explanation of the geographical distribution of the human 
species by migration. (Compare the Table of Migrations 
XV., and its explanation at the end.) 

We as yet know of no fossil remains of the hypothetical 
primseval man (Homo primigenius) who developed out of 
anthropoid apes during the tertiary period, either in 
Lemuria or in southern Asia, or possibly in Africa. But 
considering the extraordinary resemblance between the 
lowest woolly-haired men, and the highest man-like apes, 
which still exist at the present day, it requires but a slio-ht 
stretch of the imagination to conceive an intermediate form 
connecting the two, and to see in it an approximate likeness 
to the supposed primasval men, or ape-like men. The 
form of their skull was probably very long, with slantin"' 


teeth ; their hair woolly ; the colour of their skin dark, of 
a brownish tint. The hair covering the whole body was 
probably thicker than in any of the still living human 
species ; their arms comparatively longer and stronger ; their 
legs, on the other hand, knock-kneed, shorter and thinner, 
with entirely undeveloped calves; their walk hut half erect. 

This ape-like man very probably did not as yet possess 
an actual human language, that is, an articulate language 
of ideas. Human speech, as has already been remarked, 
most likely originated after the divergence of the primaeval 
species of men into different species. The number of 
primaeval languages is, however, considerably larger than 
the number of the species of men above discussed. For 
philologists have hitherto not been able to trace the four 
primseval languages of the Mediterranean species, namely, 
the Basque, Caucasian, Semitic, and Indo-Germanic to a 
single primjeval language. As little can the different Negro 
languages be derived from a common primasval language ; 
hence both these species, Mediterranean and Negro, are 
certainly polyglottonic, that is, their respective languages 
originated after the divergence of the speechless primary 
species into several races had already taken place. Perhaps 
the Mongols, the Arctic and American tribes, are likewise 
polyglottonic. The Malayan species is, however, mono- 
glottonic; aU the Polynesian and Sundanesian dialects 
and languages can be derived from a common, long since 
extinct primaeval language, which is not related to any 
other language on earth. All the other human species, 
Nubians, Dravidas, Australians, Papuans, Hottentots, and 
Kafires are likewise monoglottonic. (Compare p. 333.) 

Out of speechless primaeval man, whom we consider as 


the common primary species of all the others, there de- 
veloped in the first place — probably by natural selection — 
various species of men unknown to us, and now long since 
extinct, and who still remained at the stage of speechless 
ape-men (Alalus, or Pithecanthropus). Two of these species, 
a woolly-haired and a straight-haired, which were most 
strongly divergent, and consequently overpowered the 
others in the struggle for life, became the primary forms 
of the other remaining human species. 

The main branch of woolly-haired men (TJlotriehi) at 
first spread only over the southern hemisphere, and then 
emigrated partly eastwards, partly westwards. Remnants 
of the eastern branch are the Papuans in New Guinea and 
Melanesia, who in earlier times were diffused much fui-ther 
west (in further India and Sundanesia), and it was not 
until a late period that they were driven eastwards by the 
Malays. The Hottentots are the but little changed remnants 
of the western branch ; they immigrated to their present 
home from the north-east. It was perhaps during this 
migration that the two nearly related species of CafFres and 
Negroes branched off from them ; but it may be that they 
owe their origin to a peculiar branch of ape-like men. 

The second main branch of prlmteval straight-haired men 
(Lissotrichi), which is more capable of development, has 
probably left a but little changed remnant of its common 
primary form — ^which migrated to the south-east — in the 
ape-like natives of Australia. Probably very closely related 
to these latter are the South Asiatic pnTnceval Malays, or 
Promalays, which name we have previously given to the 
extinct, hypothetical primary form of the other six human 
species. Out of this unknown common primary form there 
seem to have arisen tln'ce diverging branches,namely, the true 


Malays, the Mongols, and the Euplocomi ; the first spread to 
the east, the second to the north, and the third westwards. 

The primseval home, or the "Centre of Creation," of the 
Malays must be looked for in the south-eastern part of the 
Asiatic continent, or possibly in the more extensive 
continent which existed at the time when further India was 
directly connected with the Sunda Archipelago and eastern 
Lemuria. From thence the Malays spread towards the 
south-east, over the Sunda Archipelago as far as Borneo, 
then wandered, diiving the Papuans before them, eastwards 
towards the Samoa and Tonga Islands, and thence 
gradually diffused over the whole of the islands of «the 
southern Pacific, to the Sandwich Islands in the north, the 
Mangareva in the east, and New Zealand in the south. A 
single branch of the Malayan tribe was driven far west- 
wards and peopled Madagascar. 

The second main branch of primaeval Malays, that is, the 
Mongols, at first also spread in Southern Asia, and, radiating 
to the east, north, and north-west, gradually peopled the 
greater part of the Asiatic continent. Of the four principal 
races of the Mongol species, the Indo-Chiiiese must perhaps 
be looked upon as the primary group, out of which at 
a later period the other Coreo-Japanese and Ural- Altaian 
races developed as diverging branches. The Mongols mi- 
grated in many ways from, w^estem Asia into Europe, where 
the species is still represented in northern Eussia and 
Scandinavia by the Fins and Lapps, in Hungary by the 
kindred Magyars, and in Turkey by the Osmanlis. 

On the other hand, a branch of the Mongols migrated 

from north-eastern Asia to America, which was probably in 

earlier times connected with the former continent by a 

broad isthmus. The Arctic tribos, or Polar men, the Hyper- 


Amharites Moora 



Ekilians I 




Samaritans (Hebrews) 

I Phoenioians I 






Primaeval Jews 

Arabians (South Semites) 



Tunese , 


Eusemites (Primaeval Semites) 
(Semites in a narrow sense) 


Tripoli tans 




Berbers (Amazirh) 



Bedschites Libians 





. Babylonians 



Ancient Egyptians 


Hamites (Dyssemites) 





Ancient Pmssians Anglo-Saxons 


High Germans 

Low Germans 


Ancient Saxons 

Baltic Eaces 

Serbians, or 


West Sclavonians 




Saxons Friesians 

Low Germans 


Goths Germans 

PrimsBval Germans 

Ancient Britons 


Ancient Scots 
Bomans Irish 



Latins Gaels 




Italo -Kelts 

Bclavo-Germans Albanese Greeks 

Primaeval Thracians 









boreans of nortli-easteni ^sia, and the Esquimaux of the 
extreme north of Ajnerica, must proLably be regarded as an 
offshoot of this branch, which became peculiarly degene- 
rated by unfavourable conditions of existence. The 
principal portion of the Mongolian immigrants, however, 
migrated to the south, and gradually spread over the whole 
of America, first over the north, later over South America. 

The third and most important main branch of primseval 
Malays, the curly -haired races, or Euplocomi, have probably 
left in the Dravidas of Hindostan and Ceylon, that species 
of man which differs least from the common primary form 
of the EuplocomL The principal portion of the latter, 
namely, the Mediterranean species, migrated from their 
primaeval home (Hindostan ?) westwards, and peopled the 
shores of the Mediterranean, south-western Asia, north 
Africa, and Europe. The Nubians, in the north-east of 
Africa, must perhaps be regarded as an offshoot of the 
primasval Semitic tribes, who migrated far across central 
Africa almost to the western shores. The various 
branches of the Indo-Germanic race have deviated furthest 
from the common primary form of ape-like men. During 
classic antiquity and the middle ages, the Romanic branch 
(the Grseco-Italo-Keltic group), one of the two main 
branches of the Indo-Germanic species, outstripped all other 
branches in the cai'eer of civilization, but at present the 
same position is occupied by the Germanic. Its chief repre- 
sentatives are the English and Germans, who are in the 
present age laying the foundation for a new period of higher 
mental development, in the recognition and completion of the 
theory of descent. The recognition of the theory of develop- 
ment and the monistic philosophy based upon it, forms the 
best criterion for the degree of man's mental development. 

( 333 ) 


N.B.— Column A denotes the Average Number of the Population In millions. 
Column B shows the Degree ot the Phyletic Development of the Species, thus Pr = 
Progressive Diifusion ; Co = Comparative Stability; Re r= lletrogresaion and Ex- 
tinction. Column C denotes the Character of the Primaival Language ; liin (Mono- 
glottonic) signifles that the Species had one Simple X'rimffival Language; PI (Poly- 
glottonic; a Compound Frimieval Language. 




(about 2 mil- 

1. PAfUAN 

2. HOTEN- 

Fleect-haieed 1 3_ ^^^^j^^ 

(about 150 tnU-^^ ^^^^^^ 
lions; V 

1 5. AUSTE/ 
/ I IAN 

I 6. Malay 

17. MOKGC 



(about 600 mil- 

Is. Arctic 

^9. Ameki- 


/lO. Deavi 

CUKLT-HAIEED \ jj^_ ^^^^^^ 


(about 600 mil- 

"""^'^ ' 12. MEDI 




Total 1350 



















( New Guinea and Melanesia, 
\ PMlipijiae Islands, Malacca 
( The extreme south of Africa 
t (The Cajje) 

( South Africa (between 30° 
t S. Lat. and 5" N. Lat.) 

( Central Africa (between the 
1 Equator and 30" N". Lat.) 

Mn { Australia 

Mn i Malacca, Sundanesia, Poly- 
( nesia, and Madagascar 

Mn ? J '^^^ greater part of Asia 
\ and northern Europe 

r The extreme north-east of 
PI .' < Asia and the extreme north 
v of America 

{The whole of America with 
the exception of the extreme 





f South Asia (Hindostan and 
I Ceylon) 

( Central Africa (Nubia and 
t Pula-land) 

In all parts of the world, 
having migrated from South 
Asia to North Africa and 
South Europe 

r In all parts of the world, 
J but predominating in Ame- 
(. rica and Asia 




Objections to the Doctrine of Filiation. — Objections of Faith and Reason. — 
Immeasnrable Length of the Geological Periods. — Transition Forms 
between Kindred Species. — Dependence of Staliility of Form on 
Inheritance, and of the Variability of Form on Adaptation. — Origin of 
very complicated Arrangement of Organisation. — Gradual Development 
of Instincts and Mental Activities. — Origin of It priori Knowledge from 
Knowledge k posteriori. — The Knowledge requisite for the Correct 
Understanding of the Doctrine of Filiation. — Necessary Interaction 
between Empiricism and Philosophy. — Proofs of the Theory of Descent, 
dinner Causal-Connection between all the Biological Series of Plieno- 
mena. — The Direct Proof of the Theory of Selection. — Eelation of the 
Theory of Descent to Anthropology. — Proofs of tlie Animal Origin of 
Man. — The Pithecoid Theory as an Inseparable Part of the Theory of 
Descent. — Induction and Deduction. — Gradual Development of the 

Unman Mind. — Body and Mind. — Human Soul and Animal Soul. ^A 

Glance at the Future. 

If in these chapters I may hope to have made the Theory of 
"Descent seem more or less probable, and to have even con- 
vinced some of my readers of its unassailable truth, yet I 
am by no means unconscious that, to most of them, during 
the perusal of my explanations, a number of objections 
more or less well founded must have occurred. Hence it 
seems absolutely necessary at the conclusion of our examin- 
ation to refute at least the most important of these, and 


at tlie same time, on the other hand, once more to set forth 
the convincing arguments which bear testimony to the 
truth of the theory of development. 

The objections which are raised to the doctrine of descent 
may be divided into two large groups :' objections of faith 
and objections of reason. The objections of the first group 
originate in the infinitely varied 'forms of faith held by 
human individuals, and need not here be taken into con- 
sideration at all. For, as I have already remarked at the 
beginning of this book, science, as an objective result of 
sensuous experience, and of the striving of human reason 
after knowledge, has nothing whatever to do with the sub- 
jective ideas of faith, which are preached by a single man 
as the direct inspu-ations or revelations of the Creator, and 
then believed in by the dependent multitude. This belief, 
very different in different nations, only begins, as is well 
known, where science ends. Natural Science behoves, 
according to the maxim of Frederick the Great, "that 
every one may go to heaven in his own fashion," and only 
necessarily enters into conflict with particular forms of 
faith where they appear to set a limit to free inquiry 
and a goal to human knowledge, beyond which we are 
not to venture. Now this is certainly the case here in 
the highest degree, for the Theory of Development applies 
itself to the solution of the greatest of scientific problems — 
that of the creation, the comiag into existence of thuigs ; 
more especially the origin of organic forms, and of man at 
their head. It is here certainly the right as well as the 
sacred duty of &ee inquiry, to fear no human authority, 
and courageously to raise the veil from the image of the 
Creator, unconcerned as to what natural truth may lie con- 


cealed beneath. The only Divine revelation which we 
recognise as true, is written everywhere in nature, and to 
every one with healthy senses and a healthy reason it is 
given to participate in the unerring revelation of this holy 
temple of nature, by his own inquiry and independent 

If we, therefore, here disregard all =objections to the Doe- 
trine of Descent which may be raised by the priests of the 
different religious faiths, we must nevertheless endeavour 
to refute the most important of those objections which seem 
more or less founded on science, and which we grant might, 
at first sight, to a certain extent captivate us and deter us 
from adopting the Doctrine of Descent. Many persons seem 
to think the length of the periods of time required the most 
important of these objections. We are not accustomed to 
deal w^ith such immense periods as are necessary for the 
history of the creation. It has abeady been mentioned that 
the periods, during which species originated by gradual 
transmutation, must not be calculated by single centuries, 
but by hundreds and by millions of centuries. Even the 
thickness of the stratified crust of the earth, the consider- 
ation of the immense space of time which was requisite for 
its deposition from water, taken together with the periods 
of elevation between the periods of depression, indicate a 
duration of time of the organic history of the earth which 
the human intellect cannot realize. We are here in much 
the same position as an astronomer in regard to infinite 
space. In the same way as the distances between the 
different planetary systems are not calculated by miles but 
by Sirius- distances, each of which comprises millions 
of miles, so the organic history of the earth must not be 


calculated by thousands of years, but by palceontological 
or geological periods, each, of whicli comprises many thou- 
sands of years, and perhaps millions, or even milliards, 
of thousands of years. It is of little importance how high 
the immeasurable length of these periods may be approxi- 
mately estimated, because we are in fact unable with our 
limited power of imagination to form a true conception of 
these periods, and because we do not as in astronomy 
possess a secure mathematical basis for fixing the approxi- 
mate length of duration in numbers. But we most positively 
deny that we see any objection to the theory of develop- 
ment in the extreme length of these periods which are so 
completely beyond the power of our imagination. It is, on 
the contrary, as I have already explained in one of the 
preceding chapters, most advisable, from a strictly philoso- 
phical point of view, to conceive these periods of creation 
to be as long as possible, and we are by so much the less 
in danger of losing ourselves in improbable hypotheses, 
the longer we conceive the periods for organic processes 
of development to have been. The longer, for example, we 
conceive the Permian period to have been, the easier it 
wiU be for us to understand how the important transmuta- 
tions took place within it which so essentially distinguish 
the fauna and flora of the Coal period from that of the 
Trias. The great disinclination which most persons have to 
assume such immeasurable periods, arises mainly from the 
fact of our having in early youth been brought up in the 
notion that the whole earth is only some thousands of 
years old. Moreover, human life, which at most attains 
the length of a century, is an extremely short space of 
time, and is not suitable as a standard for the measui'e- 


ment of geological periods. Our life is a single droj) in 
the ocean of eternity. The reader may call to mind the 
duration of life of many trees which is more than fifty 
times as long ; for example, the dragon-trees (Dracaena) and 
monkey bread-fruit trees (Adansonia), whose individual life 
exceeds a period of five thousand years ; and, on the other 
hand, the shortness of the individual life of many of the 
lower animals, for example, the infusoria, where the indi- 
vidual, as such, lives but a few days, or even but a few 
hours, contrasts no less strongly with^ human longevity. 
This comparison brings the relative nature of all measure- 
ment of time very clearly before us. If the theory of de- 
velopment be true at all, there must certainly have elapsed 
immense periods, utterly inconceivable to us; during which 
the gradual historical development of the animal and vege- 
table kingdom proceeded by the slow transformation of 
species. There is, however, not a single reason for accept- 
ing a definite limit for the length of these periods of 

A second main objection which many, and more especially 
systematic zoologists and botanists, raise against the theory 
of descent, is that no transition forms between the 
diflferent species can be found, although according to the 
theory of descent they ought to be found in great numbers. 
This objection is partly weU founded and partly not so, for 
there does exist an extraordinarily large number of tran- 
sition forms between living, as well as between extinct 
species, especially where we have an opportunity of seeino- 
and comparing very numerous individuals of kindred species. 
Those careful investigators of individual species who so 
frequently raise this objection are the very persons 


whom we constantly find checked in their special series 
of investigations by the really insuperable difficulty of 
sharply distinguishing individual species. In all sys- 
tematic works, which are in any degree thorough, one 
ineets with endless complaints, that here and there species 
cannot be distinguished because of the excessive number 
of transition forms. Hence every naturalist defines the 
limit and the number of individual species differently. 
Some zoologists and botanists, as I mentioned (vol. i. p. 276), 
assume in one and the same group of organisms ten 
species, others twenty, others a hundred or more, while 
other systematic naturalists again look upon these different 
forms only as varieties of a single " good " species. In most 
groups of forms there is, in fact, a superabundance of tran- 
sition forms and intermediate stages between the individual 
■ It is true that in many species the forms of transition 
are actually wanting, but this is easily explained by the 
principle of divergence or separation, the importance of 
which I have already explained. The circumstance that 
the struggle for existence is the more active between 
two kindred forms the closer they stand to each other, 
must necessarily favour the speedy extinction of the con- 
necting intermediate forms between the two divergent 
species. If one and the same species produce diverging 
varieties in different directions, which become new species, 
the struggle between these new forms and the common 
primary form will be the keener the less they differ from 
one another; but the stronger the divergence the less dan- 
gerous the struggle. Naturally therefore, it is principally 
the connecting intermediate forms which will in most cases 


quickly die out, while the most divergent forms remain and 
reproduce tliemselves as distinct " HQW species," In accord- 
ance with this, we in fact no longer find forms of transition 
leading to those groups which are becoming extinct, as, 
for example, among birds, are the ostriches ; and among 
mammals, the elephants, giraffes. Semi-apes, Edentata, and 
ornithorhyncus. The groups of forms approaching their 
extinction no longer produce new varieties, and naturally 
the species are what is called "good," that is, the species 
are distinctly different from one another. But in those 
animal groups where development and progress are still 
active, where the existing species deviate into many new 
species by the formation of new varieties, we find an 
abundance of transition forms which cause the greatest 
difiiculties to systematic naturalists. This is the case, for 
example, among birds with the finches ; among mammals 
with most of the rodents (more especially with those of the 
mouse and rat kind), with a number of the ruminants 
and with genuine apes, more especially with the South 
American forms (Cebus), and many others. The continual 
development of species by the formation of new varieties 
here produces a mass of intermediate forms which connect 
the so-called " good " species, which efface their boundaries, 
and render their sharp specific distinction completely 

The reason that this nevertheless does not cause a com- 
plete confusion of forms, nor a universal chaos in the struc- 
ture of animals and vegetables, lies simply in the fact 
that there is a continual counteraction at work between 
progressive adaptation on the one hand, and the retentive 
power of inheritance on the other hand. The degree of 


stability and variability manifested by every organic form 
is determined solely by the actual condition of the equi- 
librium between these two opposite functions. Inlieritance 
is the cause of the stability of species, adaptation the cause 
of their tnodification. When therefore some naturalists 
say that, according to the theory of descent, there ought 
to be a much greater variety of forms, and others again, 
that there ought to be a much greater equality of forms, 
the former under-estimate the value of inheritance and the 
latter the value of adaptation. The ratio of the interaction 
between inheritance and adaptation determines the ratio of 
the stability and variability of organic species at any given 

Another objection to the theory of descent, which, in the 
opinion of many naturalists and philosophers is of great 
weight, is that it ascribes the origin of organs which act 
for a definite purpose to causes which are either aimless 
or mechanical in their operation. This objection seems to 
be especially important in regard to those organs which 
appear so excellently adapted for a certain definite purpose 
that the most ingenious mechanician could not invent a 
more perfect organ for the purpose. Such are, above all, 
the higher sense-organs of animals, the eye and ear. J£ the 
eyes and auditory apparatus of the higher animals alone 
were known to us, they would indeed cause great and per- 
haps insurmountable difficulties. How could we come to 
the conclusion that the extraordinarily great and wonderful 
degree of perfection and conformity to purpose which we 
perceive in the eyes and ears of higher animals, is in every 
respect attained solely by natural selection? Fortunately, 
however, comparative anatomy and the history of develop- 


mcnt help us here over all obstacles; for whehinthe animal 
kingdom we follow the gradual progress towards perfection 
of the eyes and ears, step by step, we find such a finely 
graduated series of improvement, that we can clearly 
follow the development of the most complex organs through 
all the stages towards perfection. Thus, for example, the 
eye in the lowest- animal is a simple spot of pigment which 
does not yet reflect aiiy image, of external objects, but at 
most perceives and distingTiishes the different rays of light. 
Later, we find in addition to this a sensitive nerve ; then 
there gradually develops within the spot of pigment the 
first beginning of the lens, a refractive body which is now 
able to concentrate the rays of light and to reflect a definite 
image. But all the composite apparatus for the movement 
of the eye and its accommodation to variations of light and 
distance are stiU absent, namely, the various refractive 
media, the highly differentiated membrane of the optic 
nerve, etc., which are so perfectly constructed in higher 
animals. Comparative anatomy shows us an uninterrupted 
succession of all possible stages of transition, from the 
simplest organ to the most highly perfected apparatus, so 
that we can form a pretty correct idea of the slow and 
gradual formation of even such an exceedingly complex 
organ. The like gradual progi'ess which we observe in the 
development of the organ during the course of individual 
development, must have taken place in the historical 
(phyletic) origin of the organ. 

Many persons when contemplating these most perfect 
organs — which apparently were purposely invented and 
constructed by an ingenious Creator for a definite function, 
but which in reality have arisen by the aimless action 


of natural selection — experience difficulties in arriving at a 
rational understanding of them, which are similar to those 
experienced by the uncivilized tribes of nature when con- 
templating the latest complicated productions of engineer- 
ing. Savages who see a ship of the line, or a locomotive 
engine for the first time, look upon these objects as the 
productions of a supernatural being, and cannot understand 
how a man, an organism like themselves, could have pro- 
duced such an engine. Even the uneducated classes of our 
own race cannot comprehend such an intricate apparatus 
in its actual workings, nor can they understand its purely 
mechanical nature. Most natui'alists, however, as Darwin 
very justly remarks, stand in much the same position in 
regard to the forms of organisms as do savages to ships of 
the line and to locomotive engines. A rational understand- 
ing of the purely mechanical origin of organic forms can 
only be acquired by a thorough and general training in 
Biology, and by a special knowledge of comparative 
anatomy and the history of development. 

Among the remaining objection! to the Theory of Descent, 
I shall here finally refer to and refute but one more, as in 
the eyes of many unscientific men it seems to possess great 
weight. How are we, from the Theory of Descent, to conceive 
of the oriffin of the mental faculties of animals, and more 
especially their specific expressions — the so-caUed instincts ? 
This difficult subject has been so minutely discussed by 
Darwin in a special chapter of his chief work (the seventh), 
that I must refer the reader to it. We must regard instincts 
as essentially the habits of the soul acquired by adaptation, 
and transmitted and fixed by inheritance through many 
generations. Instincts are, therefore, like aU other habits. 


which, according to the laws of cunnilative adaptation 
(vol. i. p. 233) and established inheritance (vol. i. p. 216), lead 
to the origin of new functions, and thus also to new forms of 
the organs. Here, as everywhere, the interaction between 
function and organ goes hand in hand. Just as the mental 
faculties of man have been acquired by the progressive 
adaptation of the brain, and been fixed by continual trans- 
mission by inheritance, so the instincts of animals, which 
differ from them only in quantity, not in quality, have arisen 
by the gradual perfecting of their mental organ, that is, 
their central nervous system, by the interaction of Adapta- 
tion and Inheritance. Instincts, as is well known, are in- 
herited, but experiences and, consequently, new adaptations 
of the animal mind, are also transmitted by inheritance ; 
and the training of domestic animals to different mental 
activities, which wild animals are incapable of accomplish- 
ing, rests upon the possibility of mental adaptation. We 
already know a series of examples, in which such adapta- 
tions, after they had been transmitted through a succession 
of generations, finally appeared as innate instincts, and yet 
they have only been acquired from the ancestors of the 
animals. Inheritance has here caused the result of trainins- 
to become instinct. The characteristic instincts of sporting 
dogs, shepherd's dogs, and other domestic animals, and the 
natural instincts of wild animals, which they possess at 
birth, were in the first place acquired by their ancestors by 
adaptation. They may in this respect be compared to 
man's " knowledge a priori," which, like all other know- 
ledge, was originally acquired by our remote ancestors, " a 
posteriori," by sensuous experience. As I have already 
remarked, it is evident that "knowledge a priori" arose 


only by long- enduring transmission, by inheritance of 
acquired adaptations of the brain, out of originally empiric 
or experiential " knowledge k posteriori " (vol. i. p. 31). 

The objections to the Theory of Descent here discussed 
and refuted are, I believe, the most important which have 
been raised against it; I consider also that I have sufficiently 
proved to the reader their futility. The numerous other 
objections which besides these have been raised against the 
Theory of Development in general, or against its biological 
part, the Theory of Descent in particular, arise either from 
such a degree of ignorance of empirically established facts, 
or from such a want of their right understanding, and from 
such an incapacity to draw the necessary conclusions, that 
it is really not worth the trouble to go further into the 
refutation. There are only some general points in regard 
to which, I should like, in a few words, to draw attention. 

In the first place I must observe, that in. order thoroughly 
to understand the doctrine of descent, and to be convinced 
of its absolute truth, it is indisjiensable to possess a general 
knowledge of the whole of the domain of biological phe- 
nomena. The theory of descent is a biological theory, and 
hence it may with fairness and justice be demanded that 
those persons who wish to pass a valid judgment upon it 
should possess the requisite degree of biological knowledge. 
Their possessing a special empiric knowledge of this or that 
domain of zoology or botany, is not sufficient; they must 
possess a general insight into the whole series of fhenomena, 
at least in the case of one of the three organic kingdoms. 
They ought to know what universal laws result from the 
comparative morphology and physiology of organisms, but 
more especially from comparative anatomy, ftom the indi- 


vidual and the palaeontological history of development, etc. ; 
and they ought to have some idea of the deep mechanical, 
causal connection between all these series of phenomena. 
It is self-evident that a certain degree of general culture, 
and especially a philosophical education, is requisite ; ■which 
is, however, unfortunately by many persons in our day, not 
considered at all necessary. Without the necessary connec- 
tion of empirical Jowivledge and the philosophical under- 
standing of- biological phenomena, it is impossible to gain a 
thorough conviction of the truth of the TJieory of Descent. 

Now I ask, in the face of this first preliminary condition 
for a true understanding of the Theory of Descent, what we 
are to think of the confused mass of persons who have pre- 
sumed to pass a written or oral judgment upon it of an 
adverse character ? Most of them are unscientific persons, 
who either know nothing of the most important j^henomena 
of Biology, or at least possess no idea of their deeper sig- 
nificance. What should we say of an unscientific person 
who presumed to express an opinion on the cell-theory, 
without ever having seen cells ; or of one who presumed to 
question the vertebral-theory, without ever having studied 
comparative anatomy ? And yet one may meet with such 
ridiculous arrogance any day in the history of the biological 
Theory of Descent. One hears thousands of unscientific and 
but half-educated persons pass a final judgment upon it, 
although they know nothing either of botany or of zoology, 
of comparative anatomy or the theory of tissues, of palae- 
ontology or embryology. Hence it happens, as Huxley well 
says, that most of the writings published against Darwin 
are not worth the paper upon which they are written. 

We might add that there are many naturalists, and even 


celebrated zoologists and botanists, among the opponents of 
tbe Theory of Descent ; but these latter are mostly old 
stagers, "who have grown grey in quite opposite views, and 
whom we cannot expect, in the evening of their lives, to 
submit to a reform in their conception of the universe, 
w;hich has become to them a fixed idea. 

It is, moreover, expressly to be remarked, that not only 
a general insight into the ivhole domain of biological 
phenomena, but also a philosophical understanding of it, 
are the necessary preliminary conditions for : becoming 
convinced of and adopting the Theory of Descent. Now 
w^e shall find that these indispensable preliminary con- 
ditions are, imfortunately, by no means fulfilled by the 
majority of naturalists of the present day. The immense 
amount of empirical facts with which the gigantic 
advances of modem natural science have recently made us 
acquaiuted has led to a prevailing inclination for the 
special study of single phenomena and of small and 
narrow domains. This causes the knowledge of other 
paths, and especially of Nature as a great comprehensive 
whole, to be in most cases completely neglected Every one 
with sound eyes and a miscroscope, together with industry 
and patience for study, can in our day attain a certain 
degree of celebrity by microscopic "discoveries," without, 
however, deserving the name of a naturalist.: This naiaeds:' 
deserved only by him who not merely strives to know the 
individual phenomena, but who also seeks to discover their 
causal connection. Even in our own day, most pateontolo- 
gists examine and describe fossUs without knowing the 
most important facts of embryology. Embryologists, on the 
other hand, follow the history of development of a particular 


organic individual, without having an idea of the palaaon- 
tological history of the whole tribe, of which fossils are 
the records. And yet these two branches of the organic 
history of development — ontogeny, or the history of the 
individual, and phylogeny, or the history of the tribe — 
stand in the closest causal connection, and the one cannot 
be understood without the other. The same may be said of 
the systematic and the anatomical part of Biology. There 
are even now, in zoology and botany, many systematic 
naturalists who work with the erroneous idea that it is 
possible to construct a natural system of animals and plants 
simply by a careful examination of the external and readily 
accessible forms of bodies, without a deeper knowledge of 
their internal structure. On the other hand, there are 
anatomists and histologists who think it possible to obtain a 
true knowledge of animal and vegetable bodies merely by a 
most careful examination of the inner structure of the body 
of some individual species, without the comparative exami- 
nation of the bodily form of all kindred organisms. And 
yet here, as everywhere, the internal and external factors, 
to wit, Inheritance and Adaptation, stand in the closest 
mutual relation, and the individual can never be thoroughly 
understood without a comparison of it with , the whole of 
which it is a part. To those one-sided specialists we should 
like in Goethe's words to say : — 

We mnsfc, contemplating Nature, 
Part as Whole, give equal heed to : 
Nought is inward, nought is outward, 
For the inner is the outer.* 

* Musset im Naturbetrachten 
Immer Eins wie AUea achten. 
Hichtg ist drinnen, Niohts ist drauszen, 
Denn was innen, das ist auszeu. 


And again: — 

Nature has neither kernel nor stell, 
It is she that is All and All at once.* 

What is even more detrimental to the general understand- 
ing of nature as a whole than this one-sided tendency, is 
the want of a philosophical culture, and this applies to most 
of the naturalists of the present day. The various errors of 
the earlier speculative nature-philosophy made during the 
first thirty years of our century, have brought the whole of 
philosophy into such bad repute with the exact empirical 
naturalists, that they live in the strange delusion that it 
is possible to erect the edifice of natural science out of.mere 
facts, without their philosophic connection ; in short, out of 
mere knowledge, without the understanding of it. But as 
a purely speculative and absolutely philosophical system, 
which does not concern itself with the indispensable founda- 
tion of empirical facts, becomes a castle in the air, which 
the first real experiment throws to the winds; so, on the 
other hand, a purely empirical system, constructed of 
nothing but facts, remains a disorderly heap of stones, 
which will never deserve the name of an edifice. Bare 
facts established by experience are nothing but rude stones, 
and without their thoughtful valuation, without their philo- 
sophic connection, no science can be established. As I 
have already tried to impress upon my reader, the strong 
edifice of true monistic science, or what is the same thing, 
the Science of Nature, exists only by the closest interaction, 
and the reciprocal penetration of philosophy and empirical 

* Natar hat weder Kern nooh Sohale, 
AUea ist eie mit cinem Male. 


This lamentable estrangement between science and philo- 
sophy, and the rude empiricism which is now-a-days unfortu- 
nately praised by most naturalists as " exact science," have 
given rise to those strange freaks of the understanding, to 
those gross insults against elem^entary logic, and to that in- 
capacity for forming the simplest conclusions which one 
may meet with any day in all branches of science, but 
especially in zoology and botany. It is here that the 
neglect of a philosophical culture and training of the mind, 
directly avenges itself most painfully. It is not to ' be 
wondered at that the deep inner truth of the Theory of 
Descent remains a sealed book to those rude enipiricists. 
As the common proverb justly says : they cannot see the 
wood for the trees. It is only by a more . general philoso- 
phical study, and especially by a more strictly logical train- 
ing of the mind, that this sad state of things can be 
remedied. (Compare Gen. Morph. 1 63 ; ii. 447.) 

If we rightly consider this circumstance, and if we 
further reflect upon, it in connection with the empirical 
foundation of the philosophical theory of development, we 
shall at once see how we are placed respecting the oft- 
demanded proofs of the theory gf descent. The more the 
doctrine of filiation has of late years made way for itself, 
and the more all thoughtful, younger naturalists, and all 
truly biologically-educated philosophers have become con- 
vinced of its inner truth and absolute necessity, the louder 
have its opponents called for actual proofs. The same 
persons who, shortly after the publication of Darwin's work, 
declared it to be "a groundless, fantastic system," an 
" arbitrary speculation," an " ingenious dream," now kindly 
condescend to declare that the theory of descent certainly 


is a scientific " hypothesis" but that it still requires to be 
"proved." When these remarks are made by persons who 
do not possess the requisite empirico-philosophical culture, 
nor the necessary knowledge in comparative anatomy, em- 
bryology, and palaeontology, we cannot be much ofiended, 
and we refer them to" the study of those sciences. But 
when similar remarks are made by acknowledged special- 
ists, by teachers of zoology and botany, who certainly ought 
to possess a general insight into the w^hole domain of their 
science, or who are actually familiar with the facts of those 
scientific domains, then we are really at a loss what to 
say. Those who are not satisfied with the treasures of our 
present empirical knowledge of nature as a basis on which 
to establish the Theory of Descent, will not be convinced 
by any other facts which may hereafter be discovered; 
for we can conceive no circumstances "which would furnish 
stronger or a more complete testimony to the truth of the 
doctrine of filiation than is even now seen, for example, in 
the well-known facts of comparative anatomy and ontogeny. 
I must here again direct attention to the fact, that all the 
great and general laws, and all the comprelisnsive series 
of phenomena of the most different domains of biology can 
only be explained and understood by the Theory of Develop- 
ment (and especially by its biological part, the Theory of 
Descent), and that without it they remain completely inex- 
plicable and incomprehensible. The internal causal con- 
nection between them all proves the Theory of Descent to 
be the greatest inductive law of Biology. 

Before concluding, I will once more name all those series 
of inductions, all those general laws of Biology, upon which 
this comprehensive law of development is firmly based. 


(1.) The palceontological history of the development of 
organisms, the gradual appearance and the historical succes- 
sion of the different species and groups of species, the 
empirical laws of the palEeontological change of species, as 
furnished to us by the science of fossils, and more especially 
the progressive differentiation and perfecting of animal 
and vegetable groups in the successive periods of the earth's 

(2.) The individual history of development of organisms, 
embryology and metamorphology, the gradual changes in 
the slow development of the body and its particular organs, 
especially tlie progressive differentiation and perfecting of 
the organs and parts of the body in the successive periods 
of the individual development. 

(3.) The inner causal connection hetiveen ontogeny and 
phytogeny, the parallelism between the individual history 
of the development of organisms, and the palfeontological 
history of the development of their ancestors, a connection 
which is actually established by the laws of Inheritance 
and Adaptation, and which may be summed up in the 
words : ontogeny, according to the laws of inheritance and 
adaptation, repeats in its large features the outlines of 

(4.) The comparative anatomy of organisms, the proof of 
the essential agreement of the inner structure of kindred 
organisms, in spite even of the greatest difference of external 
form in the various species ; their explanation by the causal 
dependence of the internal agreement of the structure on 
Inheritance, the external dissimilarity of the bodily form 
on Adaptation. 

(5.) The inner causal connection between comparative 


anatomy and tlie history of development, the harmonious 
agreement between the laws of the gradual developmait, 
i/te progressive differentiation and perfecting, as they 
may be seen in comparative anatomy on the one hand, in 
ontogeny and paleontology on the other. 

(6.) Dysteleology, or the theory of purposelessness, the 
name I have given to the science of rudionentary organs, of 
suppressed and degenerated, aimless and inactive, parts of 
the body ; one of the most important and most interesting 
branches of comparative anatomy, which, when rightly 
estimated, is alone sufficient to refute the fundamental error 
of the teleological and dualistic conception of Nature, and 
to serve as the foundation of the mechanical and monistic 
conception of the universe. 

(7.) TJie natural system of organisms, the natural gi-oup- 
ing of all the different forms of Animals, Plants, and Protista 
into numerous smaller or larger groups, arranged beside and 
above one another ; the kindred connection of species, 
genera, families, orders, classes, tribes, etc., more especially, 
however, the arboriform, branching character of the natural 
system, which is the spontaneous result of a natural arrange- 
ment and classification of all these graduated groups or 
categories. The result attained in attempting to exhibit 
the relationships of the mere forms of organisms by a 
tabular classification is only explicable when regarded as 
the expression of their actual blood relationship ; the tree 
shape of the natural system can only be understood as the 
actual pedigree of the organisms. 

(8.) The chorology of organisms, the science of the local 
distribution of organic species, of their geographical and 
topographical dispersion over the surface of tlie earth, over 


the heights of mountains and in the depths of the ocean, 
but especially the important phenomenon that every species 
of organism proceeds from a so-called " centre of creation " 
(more coiTectly a "primceval honu," or "centre of distribu- 
tion ") ; that is, from a single locality, where it originated 
but once, and whence it spread. 

(9.) The oecology of organisins, the knowledge of the sum 
of the relations of organisms to the surrounding outer 
world, to organic and inorganic conditions of existence ; the 
so-called " economy of nature" the correlations between all 
organisms living together in one and the same locality, their 
adaptation to their surroundings, their modification in the 
struggle for existence, especially the circumstances of para- 
sitism, etc. It is just these phenomena in " the economy of 
nature " which the unscientific, on a suj^ei-ficial consideration, 
are wont to regard as the wise arrangements of a Creator 
acting for a definite purpose, but which on a more attentive 
examination show themselves to be the necessary results of 
mechanical causes. 

(10.) The unity of Biology as a whole, the deep inner con- 
nection existing between all the phenomena named and all 
the other phenomena belonging to zoology, protistics, and 
botany, and which are simply and naturally explained by a 
single common j^irinciple. This principle can be no other 
than the common derivation of all the specifically difierent 
organisms from a single, or from several absolutely simple, 
primary forms like the Monera, which possess no organs. 
The Theory of Descent, by assuming this common deriva- 
tion, throws a clear light upon these individual series of 
phenomena, as well as upon their totality, without which 
their deeper causal coimection wo\ild remain completely 


ineomprehensible to us. The opponents of the Theory of 
Descent can in no way explain any single one of these 
series of phenomena or their deeper connection with one 
another. So long as they are unable to do this, the Theory 
of Descent remains the one adequate biological theory. 

We should, on account of the grand proofs just enu- 
merated, have to adopt Lamarck's Theory of Descent for 
the explanation of biological phenomena, even if we did 
not possess Darwin's Theory of Selection. The one is so 
completely and directly proved by the other, and estab- 
lished by mechanical causes, that there remains nothing 
to be desired. The laws of Inheritance and Adaptation 
are universally acknowledged physiological facts, the 
former traceable to propagation, the latter to the nutri- 
tion of organisms. On the other hand, the struggle for 
existence is a biological fact, which with mathematical 
necessity follows from the general disproportion between 
the average number of organic individuals and the numeri- 
cal excess of their germs. But as Adaptation and Inherit- 
ance in the struggle for life are in continual interaction, 
it inevitably follows that natural selection, which every- 
where influences and continually changes organic species, 
must, by making use of divergence of character, pro- 
duce new species. Its influence is further especially 
favoured by the active and passive migrations of organisms, 
which go on everywhere. If we give these circumstances 
due consideration, the continual and gi-adual modification 
or transmutation of organic species will appear as a 
biological process, which must, according to causal law, of 
necessity follow from the actual nature of organisms and 
their mutual correlations. 


• * 

That even the origin of tnan must be explained by this 
general organic process of transmutation, and that it is 
simply as well as naturally explained by it, has, I believe, 
been sufficiently proved in my last chapter but one. I 
cannot, however, avoid here once more directing atten- 
tion to the inseparable connection between this so-called 
"theory of apes," or "pithecoid theory," and the whole 
Theory of Descent. If the latter is the greatest inductive 
law of biology, then it of necessity follows that the former 
is its most important deductive law. They stand and fall 
together. As aU depends upon a right understanding of 
this proposition, which in my opinion is very important, 
and which I have therefore several times brought before 
the reader, I may be allowed to explain it here by an 

In aU mammals known to us the centre of the nervous 
system is the spinal marrow and the brain, and the centre 
of the vascular system is a quadrupal heart, consisting of 
two principal chambers and two ante-chambers. From this 
we draw the general inductive conclusion that all mammals, 
without exception, those extinct, together with all those 
living species as yet unknown to us, as well as the species 
which we have examined, possess a like organization, a like 
heart, brain, and spinal marrow. Now if, as still happens 
every year, there be discovered in any part of the earth a 
new species of mammal, a new species of marsupial, or a 
new species of deer, or a new species of ape, every zoologist 
knows with certainty at once, without having examined its 
inner structure, that this species must possess a quadruple 
heart, a brain and spinal marrow, like all other mammals. 
Not a single naturalist would ever think of supposing that 


the central nervous system of this new species of mammal 
could possibly consist of a ventral cord with an oesopha- 
geal collar as in the insects, or of scattered pairs of 
knots as in the molluscs, or that its heart could be many- 
chambered as ia flies, or one-chambered as in the tunicates. 
This completely certain and safe conclusion, although it is 
not based upon any direct experience, is a deductive con- 
clusion. In the same way, as I have shown in a previous 
chapter, Goethe, from the comparative anatomy of mammals, 
established the general inductive conclusion that they all 
possess a mid jawbone, and afterwards drew from it the 
special deductive conclusion that man, who in aU other 
respects does not essentially differ from other mammals, 
must also possess a like mid jawbone. He maiutained this 
conclusion without having actually seen the human mid jaw- 
bone, and only proved its existence subsequently by actual 
observation (vol. i. p. 84). 

The process of induction is a logical system of forming 
conclusions /ro7?i the special to the general, by which we 
advance from many individual experiences to a general 
law; deduction, on the other hand, draws a conclusion 
from the general to the special, from a general law of 
nature to an individual case. Thus the TJieory of Descent 
is, without doubt, a great inductive law, empirically based 
upon all the biological experience cited above; the pithe- 
coid theory, on the other hand, which asserts that man has 
developed out of lower, and in the first place out of ape- 
like mammals, is a deductive law inseparably connected 
with the general inductive law. 

The pedigree of the human race, the approximate outlines 
of which I gave in the last chapter but one, of course 



remains in detail (like all tlie pedigrees of animals and 
plants previously discussed) a more or less approximate 
general hypothesis. This however does not affect the 
application of the theory of descent to man. Here, as in 
all investigations on the derivation of organisms, one must 
clearly distinguish "between the general theory of descent 
and the special hypotheses of descent. The general tlieory of 
descent claims fuU and lasting value, because it is an 
inductive law, based upon all the whole series of biological 
phenomena and their inner causal connection. Every 
special hypothesis of descent, on the other hand, has its 
special value determined by the existing condition of our 
biological knowledge, and by the extent of the objective 
empirical basis upon which we deductively establish this 
particular hypothesis. Hence, all the individual attempts 
to obtain a knowledge of the pedigree of any one group of 
organisms possesses but a temporary and conditional value, 
and any special hypothesis relating to it will become the 
more and more perfect the greater the advance we make in 
the comparative anatomy, ontogeny, and palaeontology of 
the gi'oup in question. The more, however, we enter into 
genealogical details, and the further we trace the separate 
off-shoots and branches of the joedigree, the more uncertain 
and subjective becomes our special hypothesis of descent on 
account of the incompleteness of our empirical basis. This 
however does no injury to the general theory of descent, 
which remains as the indispensable foundation for really 
profound apprehension of biological phenomena. Accord- 
ingly, there can be no doubt that we can and must, with 
full assurance, regard the derivation of man — in the first 
place, from ape-like forms; further back, from lower 


mammals, and thus continually further back to lower stages 
of the vertebrata down to their lowest invertebrate roots, 
nay, even down to a simple plastid — as a general theory. 
On the other hand, the special tracing of the human 
pedigree, the closer definition of the animal forms known 
to us, which either actually belong to the ancestors of man, 
or at least stand in very close blood relationship to them, 
will always remain a more or less approximate hypothesis 
of descent, aU the more in danger of deviating from the real 
pedigree the nearer it endeavours to approach it by search- 
ing for the individual ancestral forms. This state of things 
results from the immense gaps in our palseontological know- 
ledge, which can, under no circumstances, ever attain to 
even an approximate completeness. 

A thoughtful consideration of this important circumstance 
at once furnishes the answer to a question which is 
commonly raised in discussing this subject, namely, the 
question of scientific proofs for the animal origin of the 
hv/man race. Not only the opponents of the Theory of 
Descent, but even many of its adherents who are wanting 
in the requisite philosophical culture, look too much for 
" signs " and for special empirical advances in the science of 
nature. They await the sudden discovery of a human race 
with tails, or of a talking species of ape, or of other living 
or fossil transition forms between man and the ape, which 
shall fill the already narrow chasm between the two, and 
thus empirically " prove " the derivation of man from apes. 
Such special manifestations, were they ever so convincing 
and conclusive, would not furnish the proof desired. Un- 
thinking persons, or those unacquainted with the series of 
biological phenomena, would still be able to maintaia the 


objections to those special testimonies which they now 
maintain against our theory. 

The absolute certainty of the Theory of Descent, even in 
its application to man, is built on a more solid foundation ; 
and its true inner value can never be tested simply by 
reference to individual experience, but only by a fihilo- 
sophical comparison and estimation of the treasures of all 
our biological experiences. The inestimable importance of 
the Theory of Descent is sm'ely based upon this, that the 
theory follows of necessity (as a general inductive law) 
from the comparative synthesis of all organic phenomena 
of nature, and more especially from the triple parallelism 
of comparative anatomy, of ontogeny, and phylogeny ; and 
the pithecoid theory under all circumstances (apart from 
all special proofs) remains as a sj)ecial deductive conclu- 
sion which must of necessity be drawn from the general 
inductive law of the Theory of Descent. 

In my opinion, all depends upon a right understanding of 
this 'philosophical foundation of tJie Theory of Descent 
and of the piiUecoid theory which is inseparable from it. 
Many persons will probably admit this, and yet at the same 
time maintain that all this applies only to the iodily, not 
to the mental development of man. Now, as we have 
hitherto been occupied only with the former, it is perhaps 
necessary here to cast a glance at the latter, in order to show: 
that it is also subject to the great general law of develop- 
ment. In doing this it is above all necessary to recoUect 
that body and mind can in fact never be considered as 
distinct, but rather that both sides of nature are inseparably 
connected, and stand in the closest interaction. As even 
Goethe has clearly expressed it — "matter can never exist and 


act without mind, and mind never without matter." The 
artificial discord between mind and body, between force 
and matter, which was maintained by the erroneous dualistic 
and teleological philosophy of past times has been disposed 
of by the advances of natural science, and especially by 
the theory of development, and can no longer exist in face 
of the prevailing mechanical and monistic philosophy of our 
day. How human nature, and its position in regard to the 
rest of the universe, is to be conceived of according to the 
modern view, has been minutely discussed by Eadenhausen 
in his " Isls," ^ which is excellent and well worth perusaL 

With regard to the origiu of the human mind or the 
soul of man, we, in the first place, perceive that in every 
human individual it develops from the beginning, step 
by step and gradually, just like the body. In a newly born 
child we see that it possesses neither an independent 
consciousness, nor in fact clear ideas. These arise only 
gTadually when, by means of sensuous experience, the 
phenomena of the outer world aflect the central nervous 
system. But still the little child is wanting in all those 
difierentiated emotions of the soul which the full-grown 
man acquires only by the long experience of years. From 
this graduated development of the human soul in evpry 
single individual we can, in accordance with the inner 
causal connection between ontogeny and phylogeny, directly 
infer the gradual development of the human soxil in aU 
mankind, and further, in the whole of the vertebrate tribe. 
In its inseparable connection with the body, the human 
soul or mind has also had to pass through all those gi-adual 
stages of development, aU those various degrees of dif- 
ferentiation and perfecting, of which the hypothetical series 


of human ancestors sketched in a late chapter gives an ap- 
proximate representation. 

It is true that this conception generally greatly offends 
most persons on their first becoming acquainted with the 
Theory of Development, because more than all others it 
most strongly contradicts the traditional and mythological 
ideas, and the prejudices vi^hich have been held sacred for 
thousands of years. But like all other functions of organ- 
isms, the human soul must necessarily have historically 
developed, and the comparative or empirical study of 
animal psychology clearly shows that this development 
can only be conceived of as a gradual evolution from the 
soul of vertebrate animals, as a gradual differentiation and 
perfecting which, in the course of many thousands of 
years, has led to the glorious triumph of the human mind 
over its lower animal ancestral stages. Here, as everywhere, 
the only way to arrive at a knowledge of natural truth is to 
compare kindred phenomena, and iuvestigato their develop- 
ment. Hence we must above all, as we did in the examina- 
tion of the bodily development, compare the highest animal 
phenomena on the one hand with the lowest animal phe- 
nomena, and on the other with the lowest human phe- 
nomena. The final result of this comparison is this — that 
between the miost Jdglily developed animal souls, and the 
lowest developed human souls, there exists only a small 
quantitative, but no qualitative difference, and that this 
difference is much less than the diflference between the 
lowest and the highest human souls, or than the difference 
between the highest and the lowest animal souls. 

In order to be conviuced of this important result, it is 
above all things necessary to study and compare the mental 


life of wild savages and of children.^^ At the lowest 
stage of human mental development are the Australians, 
some tribes of the Polynesians, and the Bushmen, Hotten- 
tots, and some of the Negro tribes. Language, the chief 
characteristic of genuine men, has with them remained at the 
lowest stage of development, and hence also their formation 
of ideas has remained at a low stage. Many of these wild 
tribes have not even a name for animal, plant, colour, and 
such most simple ideas, whereas they have a word for every 
single, striking form of animal and plant, and for every 
single sound or colour. Thus even the most simple 
abstractions are wanting. In many of these languages 
there are numerals only for one, two, and three : no Austra- 
lian language counts beyond four. Very many wild tribes 
can count no further than ten or twenty, whereas some very 
clever dogs have been made to count up to forty and even 
beyond sixty. And yet the faculty of appreciating number 
is the beginning of mathematics ! Nothing, however, is per- 
haps more remarkable in this respect, than that some of the 
wildest tribes in southern Asia and eastern Africa have no 
trace whatever of the first foundations of all human civiliz- 
ation, of family life, and marriage. They live together in 
herds, like apes, generally climbing on trees and eating 
fruits ; they do not know of fire, and use stones and clubs as 
weapons, just like the higher apes. All attempts to intro- 
duce civilization among these, and many of the other tribes 
of the lowest human species, have hitherto been of no 
avail; it is impossible to implant human culture where 
the requisite soil, namely, the perfecting of the brain, is 
wanting. Not one of these tribes has ever been ennobled 
by civilization; it rather accelerates their extinction. 


They have barely risen above the lowest stage of transition 
from man-like apes to ape-like men, a stage which the pro- 
genitors of the higher human species had already passed 
through thousands of years ago.** 

Now consider, on the other hand, the highest stages of 
development of mental life in the higher vertebrate animals, 
especially birds and mammals. If, as is usually done, we 
divide the different emotions of the soul into three principal 
groups — sensation, will, and thought — we shall find in 
regard to every one of them, that the most highly developed 
birds and mammals are on a level with the lowest human 
beings, or even decidedly surpass them. The will is as dis- 
tinctly and strongly developed in higher animals as in men 
of character. In both cases it is never actually free, but 
always determined by a causal chain of ideas. (Compare 
vol. i. p. 2.37.) In like manner, the different degrees of will, 
energy, and passion are as variously graduated in higher 
animals as in man. The affections of the higher animals 
are not less tender and warm than those of matL The 
fidelity and devotion of the dog, the maternal love of the 
lioness, the conjugal love and connubial fidelity of doves 
and love-birds are proverbial, and might serve as 
examples to many men. If these virtues are to be called 
" instincts," then they deserve the same name in mankind. 
Lastly, with regard to thought, the comparative consider- 
ation of which doubtless presents the most difiiculties, this 
much may with certainty be inferred — especially from an 
examination of the comparative psychology of cultivated 
domestic animals — that the processes of thinking, here 
follow the same laws as in ourselves. Experiences every- 
where form the foundation of conceptions, and lead to the 


recognition of the connection between cause and effect. In all 
cases, as in man, it is the path of induction and deduction 
which leads to the formation of conclusions. It is evident 
that in all these respects the most highly developed animals 
stand much nearer to man than to the lower animals, 
although they are also connected with the latter by a chain 
of gradual and intermediate stages. In Wundt's excellent 
" Lectures on the Human and Animal Soul,"*'' there are a 
number of proofs of this. 

Now, if instituting comparisons in both directions, we 
place the lowest and most ape-like men (the Austral 
Negroes, Bushmen, and Andamans, etc.), on the one hand, 
together with the most highly developed animals, for in- 
stance, with apes, dogs, and elephants, and on the other 
hand, with the most highly developed men — Aristotle, 
Newton, Spinoza, Kant, Lamarck, or Goethe — we can then 
no longer consider the assertion, that the mental life of the 
higher mammals has gradually developed up to that of man, 
as in any way exaggerated. If one must draw a sharp 
boundary between them, it has to be drawn between the 
most highly developed and civilized man on the one hand, 
and the rudest savages on the other, and the latter have to 
be classed with the animals. This is, in fact, the opinion 
of many travellers, who have long watched the lowest 
human races in their native countries. Thus, for example, 
a great English traveller, who lived for a considerable time 
on the west coast of Africa, says : " I consider the negro 
to be a lower species of man, and cannot make up my 
mind to look upon him as 'a man and a brother,' for 
the o-orilla would then also have to be admitted into the 
family." Even many Christian missionaries, who, after 


long years of fruitless endeavours to civilize these lowest 
races, have abandoned the attempt, express the same 
harsh judgment, and maintain that it would be easier to 
train the most intelligent domestic animals to a moral and 
civilized life, than these unreasoning brute-like men. For 
instance, the able Austrian missionary Morlang, who tried 
for many years without the slightest success to civilize the 
ape-like negro tribes on the Upper Nile, expressly says : 
"that any mission to such savages is absolutely useless. 
They stand far below unreasomng animals ; the latter at 
least show signs of affection towards those who are kind 
towards them, whereas these brutal natives are utterly 
incapable of any feeling of gratitude." 

Now, it clearly follows from these and other testimonies, 
that the mental differences between the lowest men and the 
animals are less than those between the lowest and the 
highest men ; and if, together with this, we take into con- 
sideration the fact that in every single human child mental 
life develops slowly, gradually, and step by step, from the 
lowest condition of animal unconsciousness, need we still 
feel ofi'ended when told that the mind of the w^hole human 
race has in like manner gone through a process of slow, 
gradual, and historical development ? Can we find it 
" degrading " to the human soul that, by a long and slow 
process of differentiation and perfecting, it has very 
gradually developed out of the soul of vertebrate animals ? 
I freely acknowledge that this objection, which is at pre- 
sent raised by many against the pithecoid theory, is quite 
incomprehensible to me. On this point Bernhard Cotta, 
in his excellent " Geologie der Gegenwart," very justly 
remarks : " Our ancestors may be a great honour to us ; 
but it is much better if we are an honour to them ! " ^ 


Our Theory of Development explains the origin of man 
and the course of his historical development in the only 
na.tural manner. We see in his gradually aseensive develop- 
ment out of the lower vertebrata, the greatest triumph of 
humanity over the whole of the rest of Nature. We are 
proud of having so immensely outstripped our lower 
animal ancestors, and derive from it the consoling assurance 
that in future also, mankind, as a whole, will follow the 
glorious career of progressive development, and attain a stUl 
higher degree of mental perfection. When viewed ia this 
light, the Theory of Descent as applied to man opens up 
the most encouraging prospects for the future, and frees us 
from all those anxious fears which have been the scarecrows 
of onx opponents. 

We can even now foresee with certainty that the com- 
plete victory of our Theory of Development will bear 
immensely rich fruits — fruits which have no equal in the 
whole history of the civilization of mankind. Its first and 
most direct result — the complete reform of Biology — ^will 
necessarily be followed by a still more important and fruit- 
ful reform of Anthropology. From this new theory of man 
there will be developed a new pJdlosophy, not like most of 
the airy systems of metaphysical speculation hitherto 
prevalent, but one founded upon the solid ground of Com- 
parative Zoology. A beginning of this has already been 
made by the great English phHosox^her Herbert Spencer.** 
Just as this new monistic philosophy first opens up to us 
a true understanding of the real xmiverse, so its appli- 
cation to practical human life must open up a new road 
towards moral perfection. By its aid we shall at last begin 
to raise ourselves out of the state of social barbarism in 


■vvliichj notwithstanding the much vaunted civilization of 
our century, we are still plunged. For, unfortunately, it 
is only too true, as Alfred Wallace remarks with regard 
to this, at the end of his book of travels: "Compared 
Avith our wondrous progress in physical science and its 
practical applications, our system of government, of admin- 
istering justice, of national education, and our whole social 
and moral organisation remains in a state of barbarism." 

This social and moral barbarism we shall never overcome 
by the artificial and perverse training, the one-sided and 
defective teaching, the inner untruth and the external tinsel, 
of our present state of civilization. It is above all things 
necessary to make a complete and honest return to Nature 
and to natural relations. This return, however, wiU only 
become possible when man sees and understands his true 
" place in nature." He will then, as Fritz Eatzel has 
excellently remarked,*'' "no longer consider himself an 
exception to natural laws, but begin to seek for what is 
lawful in his own actions and thoughts, and endeavour 
to lead a life according to natural laws." He will come 
to arrange his life with his fellow- creatures — that is, the 
family and the state — not according to the laws of distant 
centuries, but according to the rational principles deduced 
from knowledge of nature. Politics, morals, and the prin- 
ciples of justice, which are still drawn from all possible 
sources, will have to be formed in accordance with natural 
laws only. An existence worthy of man, which has been talked 
of for thousands of years, wiU at length become a reality. 

The highest function of the human mind is perfect know- 
ledge, fully developed consciousness, and the moral activity 
arising from it. " I^iow thyself ! " was the cry of the philo- 


sopliers of antiquity to their fello-w-men wlio were striving 
to ennoble tliemselves. "Know thyself!" is the cry of the 
Theory of Development, not merely to the individual, but 
to all mankind. And whilst increased knowledge of self 
becomes, in the case of every individual man, a strong force 
urging to an increased attention to conduct, mankind as 
a whole wiU be led to a higher path of moral perfection 
by the knowledge of its true origin and its actual position 
in Nature. The simple religion of Nature, which grows 
from a true knowledge of Her, and of Her inexhaustible 
store of revelations, will in future ennoble and perfect the 
development of mankind far beyond that degree which can 
possibly be attained under the influence of the multifarious 
religions of the churches of the various nations, — religions 
resting on a blind belief in the vague secrets and mythical 
revelations of a sacerdotal caste. Future centuries will 
celebrate our age, which was occupied with laying the 
foundations of the Doctrine of Descent, as the new era in 
which began a period of human development, rich in bless- 
ings, — a period which was characterized by the victory of 
free inquiry over the despotism of authority, and by the 
powerful ennobling influence of the Monistic Philosophy. 


The stttdy of which is recommended to the Header. 

1. Charles Banvin, On the Origin of Species by means of 
Natural Selection ; or, the Preservation of Favoured Races in 
the Struggle for Life. London, 1859. 5th Edition, 1869. 

2. Jean Lamarclc, Philosophie Zoologique, ou Exposition des 
Considerations relatives a I'histoire naturelle des animauz ; a la 
diversite de leur organisation et des f acultes, qu'ils en obtiennent ; 
aax causes physiques, qui maintiennent en eux la vie et donnent 
lieu aux mouvemens, qu'ils executent ; enfin, a celles qui 
produisent, les unes le sentiment, et les autres I'intelligence de 
ceax qui en sont doues. 2 Tomes. Paris, 1809. 

3. Wolfgang Goethe, Zur Morphologie : Bildung nnd 
Umbildung organischer Naturen. Die Metamorphose der 
Pflanzen, 1790. Osteologie, 1786. Vortriige iiber die drei 
ersten Capitel des Entwurfs einer allgemeinen Einleitung in 
die vergleichende Anatomie, ausgehend von der Osteologie, 
1786. Zur Naturwissenschaft im Allgemeinen, 1780-1832. 

(Wolfgang Goethe, Contributions to Morphology : Fonnation 
and Transformation of Organic Natures. The Metamorphosis of 
Plants, 1790. Osteology, 1786. Lectures on the first three 
chapters of an Attempt at a General Introduction to Compara- 
tive Anatomy, beginning with Osteology, 1786. Contributions 
to the Science of Nature in general, 1780-1832.) 


4. Erjisi HaecJcel, Generelle MorpTiologie der Organismen : 
Allgemeine Gmndziige der orgaaisclien Fonnenwissenscliaft, 
mechaniscli begriindet durcli die von Charles Darwin reformirte 
Descendenz-theorie. I. Band, Allgemeine Anatomie der Organ- 
ismen, Oder Wissenschaft von den cntwiekelten organisclien 
Formcn. II. Band, Allgemeine Entwickelnngsgescliiolite der 
Organismen, oder Wissensehaft von den entstehenden organis- 
chen Pormen. Berlin, 18C6. 

(Ernst Haeckel, General Morphology of Organisms ; General 
Outlines of the Science of Organic Forms based on Mechanical 
Principles through the Theory of Descent as reformed by 
Charles Darwin. Vol. I., General Anatomy of Organisms ; or, 
the Science of Fully Developed Organic Forms. Vol. II., General 
History of the Development of Organisms ; or, the Science of 
Organic Forms in their Origin. Berlin, 1866.) 

5. Loids Agassiz, An Essay on Classification. Contributions 
to the Natural History of the United States. Boston. Vol. I., 


6. August ScMeiclier, Die Darwin'sche Theorie nnd die 
Sprachwissenschaft. Weimar, 1863. 

(August Schleicher, Darwin's Theory and the Science of 
Ijanguage. Weimar, 1863.) 

7. IL J. Scldeiden, Grundziige der -wissenschaftlichen 
Eotanik (die Botanik als inductive Wissenschaft). 2 Biinde. 
Leipzig, 1849. 

(M. J. Schleiden, Principles of Scientific Botany (Botany as 
an Inductive Science). 2 Vols. Leipzig, 1849. Translated 
by Edwin Lankester, M.D\, F.R.S. London, 1849.) 

8. Franz linger, Versuch einer Geschichte der Pflanzenwelt. 
Wien, 1852. 

(Franz Unger, Essay on the History of the Vegetable 
Kingdom. Vienna, 1852.) 


9. Victor Cants, System der tHerisclien. Morphologie. 
Leipzig, 1853. 

(Victor Carus, System of Animal Morphology. Leipzig, 1853.) 

10. Louis BiicJmer, Kraft und Stoif. Empiriscli-naturpliilo 
Eopliisolie Studicn in allgemein verstandlicher Darstellung 
EranMort, 1855, 3 Anflage. 1867, 9 Auflage. 

(Louis Biichner, Force and Matter. Studies in tlie Empirical 
Philosopliy of Nature, treated popularly. Frankfort, 1855, 3rd 
Edition. 1867, 9tli Edition.) 

11. Charles Lyell, Principles of Geology. London, 1830. 
loth Edition, 1868. 

12. Albert Lange, GescHclite des Materialismus und Kritik 
seiner Bedeutung in der Gegen wart. Iserlohn, 1866. 

(Albert Lange, History of Materialism, and a Criticism of its 
Importance at the Present Time. Iserlohn, 186G.) 

13. Charles Darwin, Voyage of the Beaglo. London. 

14. Charles Darwin, The Variation of Animals and Plants 
under Domestication. 2 Vols. London, 1868. 

15. Ernst Haeakel, Studien liber Moneren und andere 
Protisten, nebst einer Rede iiber Entwickelungsgang und 
Aufgabe der Zoologie. Mit 6 Kupfertafeln. Leipzig, 1870. 

(Ernst Haeokel, Studies on the Monera and other Protista, 
together with a Discourse on the BTolution and the Problems 
of Zoology. With 6 Copper-plates. Leipzig, 1870.) 

16. Fritz Mailer, Fiir Darwin. Leipzig, 1864. 

(Fritz Miiller, For Darwin. Translated by W. S. Dallas. 
London, Murray.) 

; 17. Thomas Suxley, On our Knowledge of the Causes of 
/the Phenomena of Organic Nature. Six Popular Lectures. 
/ London, Hardwicke, 1862. 


18. H. 6. Bronn, MorpTiologisclie Siudicn iibcr die 
Gestaltungsgesetze der Naturkorper iiberhaupt, und der 
Organischen insbesondere. Leipzig und Heidelberg, 1858. 

(H. G. Broun, Moi'pbological Studies on tbe Laws of Form 
of Natural Bodies in General, and of Organic Bodies in Par- 
ticular. Leipzig and Heidelberg, 1858.) 

19. H. G. Bronn, TJntersuobungen iiber die Entwickelungs- 
gesetze der organiscHen Welt wahrend der Bildungszeit unserer 
Erdoberfliicbe. Stuttgart, 1858. 

(H. G. Bronn, Investigations on the Laws of Development of 
the Organic World during the Time of the Formation of the 
Earth's Crast. Stuttgart, 1858.) 

20. Carl Ernst Bar, Ueber Entwickelungsgeschichte der 
Thiere. Beobachtung und Reflexion. 2 Biinde. 1828. 

(Carl Ernst Bar, On the History of the Development of 
Animals. Observation and Reflection. 2 Vols. 1828.) 

21. Carl Gogoiilaur, Grundziige der vcrgleichenden Anatomie. 
Leipzig, 1859. 2 (Umgsarbeltete) Auflage, 1870. 

(Carl Gegenbaur, Outlines of Comparative Anatomy. 
Leipzig, 1859. 2nd (Revised) Edition, 1870.) 

22. Immanuel Kant, Allgemeine Naturgeschichte und 
Theorie des Himmels, oder Versuch von der Verfassnng und dem 
mechanisohen Ursprungo des ganzen Weltgebiiudes nach New- 
ton'schen Grundsatzen abgehandelt. Konigsberg, 1765. 

(Immanuel Kant, General History of Nature and Theory of 
the Heavens ; or. Essay on the Constitution and the Mechanical 
Origin of the whole Universe treated according to Newton's 
Principles. Konigsberg, 1765.) 

23. Ernst Haeclcel, Die Radiolarien. Eine Monographie. 
Mit einem Atlas von 35 Kupfertafeln. Berlin, 1862. 

(Ernst Haeckel, The Radiolaria. A Monograph, with Atlas 
containing 35 Copper- plates. Berlin, 1862.) 


24. August Weismann, TJeber den Einflusz der Isolirung auf 
die Artbildung. Leipzig, 1872. 

(August Weismann, On tlie Influence of Isolation on the 
Formation of Species. Leipzig, 1872.) 

25. Ernst Haeckel, TJeber die Enstebung nnd den Stammbanm 
des Menscbengescblechts. Zwei Vortrage in der Sammluiig 
gem.einTerstandlicher wissenschaftlicher Vortrage, herattsge- 
geben Ton. Vircbow xrnd Holtzendorfi. Berlin, 18G8. 2 Auflage, 

(Ernst Haeckel, On tbe Origin and tbe Pedigree of tbe Ilnman 
Race. Two Lectures in tbe Collection of Popular Scientific 
Lectures, edited by Vircbow and Holtzendorfl:. Berbn, 1868. 
2nd Edition, 1870.) 

26. Thomas Huxley, Evidences as to Man's Place in Nature. 
Tbrce Parts : 1. On tbe Natural History of tbe Man-Uke Apes. 
2. On tbe Relations of Man to tbe Lower Animals. 3. On some 
Eossil Remains of Man. London, Williams & Norgate, 

27. Garl Vogt, Yorlesnngen iiber den Menscben, seine 
Stellung in der Scbopfung und in der Gescbicbte der Erde. 2 
Bande. Giessen, 1863. 

(Carl Vogt, Lectures on Man, bis Place in Creation and in tbe 
History of tbe Earth. 2 Vols. Giessen, 1863.) 

28. FriedricJh Molle, Der Menscb, seine Abstammung und 
Gesittung im Licbte der Darwin'scben Lebre von der Art- 
Bntstebung, und auf Grund der neueren geologiscben Entdeck- 
tingen dargestellt. Fi-ankfurt-a-M., 1866. 

(Friedrich Rollc, Man, bis Derivation and Civilization, in tbe 
Light of Darwin's Theory of tbe Origin of Species, based on 
Recent Geological Discoveries. Frankfort-a-M., 1866.) 

29. JEduard Reich, Die allgemeine Naturlebre des Menscben. 
Giessen, 1865. 

(Eduard Reich, Tbe General Natural History of Man. 
Giessen, 1865.) 


80. Oliarhs Lyell, Tlie Antiquity of Man. London, Murray. 

31. BernJiard Cotta, Die Geologie der Gegenwart. Leipzig, 

(Bemliard Cotta, The Geology of the Present Day.) 

32. Karl Zittel, Aus der Urzeit. Bilder aus der Schopfungs- 
geschichte. Miinchen, 1871. 

(Karl Zittel, Primceval Times. Pictures from the History of 
Creation. Munich, 1871.) 

33. C. liadenlmusen, Isis. Der Meusch nnd die Welt. 4 
Bande. Hambiirg, 1863. 2 Anflage, 1871. 

(C. Radenhausen, Isis. Man and the Universe. 4 Vols. 
Hamburg, 1863. 2nd Edition, 1871.) 

34. August ScJdeicher, Ueber dor Bedeutung der Sprache fiir 
die Naturgeschichte des Menschen. Weimar, 186-5. 

(August Schleicher, On the Importance of Language to the 
Natural History of Man. Weimar, 1865). 

35. Willielm BleeJc, Ueber den Ursprung der Sprache. Her- 
ausgegeben mit einem Vorwort von Ernst Haeckel. Weimar, 

(Wilhelm Bleek, On the Origin of Language. Edited and with 
a Preface by Ernst Haeckel. Weimar, 1868.) 

36. Alfred Mussel Wallace, The Malayan Archipelago. 
London, Macmillan. 

37. Ernst Haockel, Ueber Arbcitstheilung in Watur- nnd 
Menschenleben. Sammlung gemeinverstandlieher wissen- 
schaftlicher Vortrage, herausgegeben von Tirchow und 
Holtzendorff. 4 Serie. 1869. Heft 78. 

(Ernst Haeckel, On Differentiation in Nature and in Human 
Life. A Collection of Popular Scientific Lectures, edited by 
Virchow and Holtzendorff. 4th Series. 1869. No. 78.) 


38. Hermann Helmholtz, Populare wissonscliaftliclie Vortrage. 
Braunsoiiweig, 1871. 

(Hermann Holmlioltz, Popular Scientific Lectures. Brunswick, 

39. Alexander Humboldt, Ansicliten der Natur. Stuttgart, 

(Alexander Humboldt, Yiews of Kature, Stuttgart, 1826.) 

40. Moritz Wagner, Die Darwin'sclie Theorie und das 
Migrationsgesetz der Organismen. Leipzig, 1868. 

(Moritz Wagner, Darwin's Theory and the Law of the Migra- 
tion of Organisms. Leipzig, 1868.) 

41. Rudolf Virchoiu, Vier Eeden iibcr Leben und Krantsein. 
Berlin, 1862. 

(Rudolf Virchow, Four Discourses on Life and Disease. 
Berlin, 1862.) 

42. Friedrich Miiller, Ethnographie (Reise der oster- 
reichischen Fregatte Novara. Anthropologischer Theil. 3 
Abtheilung). Wien, 1868. 

(Friedrich Miiller, Ethnography (Voyage of the Austrian 
Frigate Novara. Anthropological Part. 3rd Part). Vienna, 

43. Jjudwig BiicJiner, Die Stellung des Menschen in der 
Natur, in Vergangenheit, Gegenwart und Zukunft. Leipzig, 

(Ludwig Biichner, Man's Place in Nature in the Past, the 
Present, and the Future. Leipzig, 1870.) 

44. John LuhhocJc, Prehistoric Times. London, 1867. 

45. Herbert Spencer, A System of Philosophy. (1. First 
Principles. 2. Principles of Biology. 3. Principles of 
Psychology, etc) London, 1867. 2nd Edition. 



46. Willielm Wundt, Vorlesungen liber die Mensclien- nnd 
Thierseele. Leipzig, 1863. 

(Wilhelm Wundt, Lectures on the Human and Animal Soul, 
Leipzig, 1863.) 

47. Fritz Batzel, Sein und Warden der organisclicn Welt. 
Eine populare SchopfungsgeEchichte. Leipzig, 1869. 

(Fritz Ratzel, Nature and Origin of tlie Organic World. 
A Popular History of Creation. Leipzig, 1869.) 

48. Charles Darwin, The Descent of Man, and Selection in 
Eelatioa to Sex. 2 Vols. London, 1871. 



Plate facing Title-page, 

Developmental History of a Calcareous Sponge (Olyntlius). 
Compare vol, ii, p. 140. The egg of the Olynthus (Fig. 9), 
which represents the commoii ancestral form of all Calcareous 
Sponges, is a simple cell (Fig. 1). From this there arises, by 
repeated division (Fig. 2), a globular, mulberry-like heap of 
numerous equi-formal cells (Morula, Fig. 3 ; vol. ii. p. 125. 
As the result of the change of these cells into an outer series of 
clear ciliated cells (Exoderm) and an inner series of dark, non- 
ciliated cells (Entoderm), the ciliated larva, or Planula, makes 
its appearance. This is oval in shape, and forms a cavity in 
its centre (gastric cavity, or primitive stomach, Fig. 6 g.), with. 
an opening (mouth-opening, or primitive mouth. Fig. 6 o) ; the 
wall of the gastric cavity consists of two layers of cells, or 
germ-layers, the outer cihated Exoderm (e) and the inner non- 
ciliated Entoderm (i). Thus arises the exceedingly important 
stomach-larva, or Grastrula, which reappears in the most different 
tribes of animals as a common larval form (Fig. 6, seen from the 
surface ; Fig. 6, in long section. Compare, vol. ii. pp. 126 and 
281). After the Gastrula has swum about for some time in the 
sea, it fastens itself securely to the sea-bottom, loses its outer 
vibratile processes, or cilia, and changes into the Ascula (Fig. 7, 
seen from the surface ; Fig. 8, in long section ; letters as in Fig, 6) . 
This Ascula is the recapitulative form, according to the biogenetic 


fundamental law, tie common ancestor of all Zoophytes, iiam.ely, 
the Protascns (vol. ii. pp. 129, 13-3). By the development of pores 
in the wall of the stomach and of three-rayed calcareous spicules, 
the Ascula changes into the Olynthns (Fig. 9.) In Fig. 9 a 
piece is cut out from, the stomach- wall of the Olynthus in order 
to show the inside of the stomachal cavity, and the eggs which 
are forming on the surface (g). From the Olynthus the most 
various forms of Calcareous Sponges can develop. One of the 
most remarkable is the Ascometra (Fig. 10), a stock or colony 
from which different species, and in fact different generic forms, 
grow (on the left Olynthus, in the middle JSTardorus, on the right 
Soleniscus, etc., etc.). Further details as to these most interest- 
ing forms, and their high importance for the Theory of Descent, 
may be found in my "Monograph of the Calcareous Sponges" 
(1872), especially in the first volume. (Compare vol. ii. pp. 160, 

Plate I. (JBetwcen pages 184 and 185, Vol. J.) 

History of the Life of the most Simple Organism, a Moneron 
(Protomyxa aurantiaca). Compare vol. i. p. 184, and vol. ii. p. 63. 
The plate is a smaller copy of the drawing in my " Monographie 
der Moneren " (Biologische Studien, 1 Heft, 1870 ; Taf . 1), of 
the developmental history of the Protomyxa aurantiaca ; I have 
there also given a detailed description of this remarkable 
Moneron (p. 11-30). I discovered this most simple organism 
in January, 1867, during a stay in Lanzarote, one of the Canary 
Islands ; and moreover I found it either adhering to, or creeping 
about on the white calcareous shells of a small Cephalopod (vol. ii. 
p. 162), the Spirula Peronii, which float there in masses on the 
surface of the ocean, or are thrown up on the shore. The 
Protomyxa aurantiaca is distinguished from, the other Monera 
by the beautiful and bright orange-red colour of its perfectly 
simple body, which consists merely of primseval slime, or 
protoplasm. The fully developed Moneron is represented in 
Figs. 11 and 12, very much enlarged. When it is hungry (Fig, 
11), there radiate from the surface of the globular -corpuscule 


of plasm, quantities of tree-shaped, 'branc'hing and motile 
threads (pseudo-feet, or pseudo-podia), which do not become 
retiformly connected. When, however, the Moneron eats 
(Fig. 12), the mucous threads become variously connected, 
form net-works and enclose the extraneous corpuscule which 
serves as food, which the threads afterwards draw into the 
interior of the Protomyxa. Thus in Fig. 12 (above on the 
right), a silicious and ciliated Whip-swimmer (Peridinium, vol. ii. 
pp. 51, 57), has just been caught by the extended mucous 
filaments, and has been drawn iuto the interior of the mucous 
globule, in which there already are several half digested silicious 
infusoria (Tintinoida), and Diatomeas (Isthmia). Now, when 
the Protomyxa Las eaten and grown. sufEciently, it draws in all 
its mucous filaments (Fig. 15), and contracts into the form of a 
globule (Fig. 16 and Fig. 1), In this state of repose the globule 
secretes a simple gelatinous covering (Fig. 2), and after a 
time subdivides into a large number of small mucous globules 
(Fig. 3). These soon commence to move, become pear-shaped 
(Fig. 4), break through the common covering (Fig. 6), and then 
swim about freely in the ocean by means of a delicate whip- 
shaped process, like the Flagellata (vol. ii. p. 57, Fig. 11). When 
they meet a Spirula shell, or any other suitable object, they 
adhere to it, draw in their whip, and creep slowly about on it by 
means of form-changing processes (Figs. 6, 7, 8), like Protamoabae 
(vol. i. p. 186, vol. ii. p. 62). These small mucous corpuacules 
take food (Figs. 9, 10), and attain their full grown form (Figs. 
11, 12), either by simple growth or by several of them fusing to 
form a larger protoplasmic mass (Plasmodium, Figs. 13, 14). 

Plates II. and III. {Between pages 294 and 295, Vol. J.) 

Germs or Emhryos of four different Vertebrate Animals, namely. 
Tortoise (A and E), Hen (B and F), Dog (G and G), and Man 
(D and if). Figs. A, D, an early stage of development; Figs, 
i?, H, a later stage. AU the eight embryos are represented as 
seen from the right side, the curved back turned to the left. 


Figs. A and i? are seven times enlarged, I'igs. G and D five times, 
Figs. jE and H four times. Plate II. exHibits tlie very close blood 
.relationsliip between birds and reptiles ; Plate III. that between 
man and the otlicr mammals. 

Plate IV, {Bebveen pages 34 and 35, Vol. II.) 

The Hand, or Fore Foot, of nine different Mammals. This plate 
is intended to show the importance of Comparative Anatomy to 
Phylogeny, in as much as it proves how the internal skeleton of 
the limbs is continually preserved by inheritance, although the 
CKtemal form is extremely changed by adaptation. The bones of 
the skeleton of the hand are drawn in white lines on the brown 
flesh and skin which surrounds them. All the nine hands are 
represented in the same position, namely the wrist (where the arm 
would be joined to it) is placed above, whilst the ends of the fingers 
or toes are turned downwards. The thumb, or the first (large) 
fore-toe is on the left in every figure ; the little finger, or fifth toe 
is to the right at the edge of the hand. Each hand consists of 
three parts, namely (i.) the wrist (carpus), composed of two cross 
rows of short bones (at the upper side of the hand) ; (ii.) the 
mid-hand (metacarpus), composed of five long and strong bones 
(marked in the centre of the hand by the numbers 1-5) ; and 
(iii.) the five fingers, or fore toes (digiti), every one of which 
again consists of several (mostly from two to three), toe-pieces, 
or phalanges. The hand of man (Fig. 1), in regard to its entire 
formation, stands mid- way between that of the two large human 
apes, namely, that of the gorilla, (Fig. 2), and that of the 
orang (Fig. 3). The fore paw of the dog (Fig. 4), is more 
different, and the hand or breast fin of the seal (Fig. 5) still 
more so. The adaptation of the hand to the movement of swim- 
ming, and its transformation into a fin for steering, is still more 
complete in the dolphin (Ziphius, Fig. 6). The extended fingers 
and bones of the central hand here have remained short and strong 
in the swimming membrane, but they have become extremely long 
and thin in the lat (Fig. 7), where the hand has developed into 
a wing. The extreme opposite of the latter formation is the hand 


of tlie mole (Fig. 8), wHich has acquired a powerful spade-like 
form for digging, witli fingers wticli tave become extremely short 
and thick. What is far more like the human, hand than these latter 
forms, is the fore paw of the lowest and most imperfect of all 
mammals, the Australian healced aninial (Ornithorhynchus, Fig. 
9), which in its whole structure stands nearer to the common, 
extinct, primary form of mammalia, than any known species. 
Hence man diiiers less in the formation of the hand from this 
common primary form than from the bat, mole, dolphin, seal, 
and many other mammals. 

Plate V. (Between pages 84 and 85, Vol. II.) 

Monophyletic, or One-rooted Pedigree of the Vegetaile Kingdom^ 
representing the hypothesis of the common derivation of all 
plants, and the historical development of the different groups of 
plants during the paleeontological periods of the earth's history. 
The horizontal lines denote the different smaller and larger 
periods of the organic history of the earth (which are spoken of ia 
vol. ii. p. 14), and during which the strata containing fossils were 
deposited. The Tertical lines separate the different main-classes 
and classes of the vegetable kingdom from one another. The 
arboriform and branching lines indicate, in an approximate 
manner, by their greater or less number and thickness, the 
greater or less degree of development, differentiation, and 
perfecting which each class probably attained in each geological 
period. (Compare vol. ii. pp. 82, 83.) 

Plate VI. (Between pages 130 and 131, Vol. IL") 

Monophyletic, or One-rooted Pedigree of the Animal Kingdom, 
representing the historical growth of the six animal tribes during 
the paleeontological periods of the organic history of the earth. 
The horizontal lines g h, i h, I m, and n divide the five large 
periods of the organic history of the earth one from another. 
The field g ai h comprises the archilithic, the field i g h h, the 
palEeolithic, the field I ih m the mesolithic, and the field n I om 


the cenolitliic period. The short, anthropolithic period is indi- 
cated by the line n 0. (Compare vol. ii. p. 14.) The height of the 
separate fields corresponds with the relative length of the periods 
indicated by them, as they may approximately be estimated from 
the relative thickness of the neptunic strata deposited between 
them. (Compare vol. ii. p. 22.) The archilithic and primordial 
period alone, during which the Laurentian, Cambrian, and Silurian 
strata were deposited, was probably considerably longer than the 
four subsequent periods taken together. (Compare vol. ii. pp. 10, 
20). In all probability the two tribes of worms and Zoophytes 
attained their full development durmg the mid-primordial period 
(in the Cambrian system) ; the star-fishes and molluscs probably 
somewhat later (in the Silurian system); whereas the articulata 
and vertebrata are still increasing in variety and perfection. 

ruTU VII. (Beiuxen pages 14G and 147, Vol II.) 

Orovp of Animal-Trees (^Zoopliytes, or Cadenierata) in the 
Mediterranean. On the upper half of the plate is a swarm of 
swimming medusee and otcnophora ; on the lower half a few 
bunches of corals and hydroid polyps adhering to the bottom 
of the sea. (Compare the system of Zoophytes, vol. ii. p. 132, 
and on the oj)posite page their pedigree.) Among the adher- 
ing Zoophytes at the bottom of the ocean there is, below on 
the right hand, a large coral-colony (1), which is closely akin 
to the rod precious coral (Eucorallium), and like the latter 
belongs to the group of corals with eight rays (Octocoralla 
Gorgonida) ; the single individuals (or persons) of the branchino- 
stock have the foi-m of a star with eight rays, consistino' of eicht 
tentacles, which surround the mouth. (Octocoralla, vol. ii. p. 143). 
Directly below and in front of it (quite below on the right), is a 
small bush of hydroid polyps (2), belonging to the group of bell- 
polyps, or Campanularise (vol. ii. p. 146). A larger stock of hydroid 
polyps (3), belonging to the group of tube-polyps, or Tubullarife, 
rises, to the left, on the opposite side, with its long thin branches. 
At its base is spread a stock of silicious sponges (Halichondria) 


(4), with sliort, fingor-sliaped brandies (vol. ii. p. 139). Beliind it, 
below on the left (6), is a very large marine rose (Actinia), a single 
individual from the class of six-rayed corals (Hexacoralla, vol. ii. 
p. 143). Its low, cylindrical body has a crown of very numerous 
and large leaf-shaped tentacles. Below, in the centre of the 
ground (6), is a sea-anemone (Cereanthus) from the group of four- 
fold corals (Tetracoralla) . Lastly, on a small hill on the bottom 
of the sea, there rises, on the right above the corals (1) a 
cup-polyp (Lucernaria), as the representative of the stalked- 
jellies. (Podactinaria, or Calycozoa, vol. ii. p. 144.) Its cup- 
shaped, stalked body (7) eiglit globular clusters of small, 
knotted tentacles on its rim. 

Among the swimmwg Zoophytes whicb occupy tbe upper lialf 
of Plate VII., the hydromeduso) are especially remarkable, on 
account of their alteration of generation. (Compare vol. i. p. 206) . 
Directly above the Lucernaria (7) floats a small tiara jeUy 
(Oceania), whose bell-shaped body has a process like a dome, 
the form of a papal tiara (8). From the opening of the bell 
there bangs a wreath of very fine and long tentacles. This 
Oceania is the offspring of a tube-polyp, resembling the adhering 
Tubularia below on the left (3). Beside this latter, on the left, 
swims a large but very delicate hair-jelly (^quorea). Its disc- 
shaped, slightly arched body is just drawing itself together, and 
pressing water out of the cavity of the cup lying below (9). 
The numerous, long, and fine hair-like tentacles wbich hang down 
from the rim of the cup are drawn by tbe ejected water into a 
conical bunch, which towards the centre turns upwards like a 
collar, and is thrown into folds. Above, in the middle of the 
cavity of the cup, hangs the stomach, the mouth of which is 
surrounded by four lobes. This jEquorea is derived froni a 
small bell-polyp, resembling the Campanularia (2). The small, 
slightly arched cap-jelly (Eucope), swimming above in the centre 
(10), is likewise derived from a similar bell-polyp. In these three 
last cases (8, 9, 10), as in the majority of the hydromeduste, the 
alternation of generation consists in the freely swimming medusa 
(8, 9, 10), arising by the formation of buds (therefore by non- 


sexual generation, yol. i. p. 192), from adhering liydroid polyps 
(2, 3). These latter, however, originate out of the fructified eggs 
of the medusas (therefore by sexual generation, vol. i. p. 196). 
Hence the non-sexual, adhering generation of polyps (I., III., 
v., etc.) regularly alternates with the sexual, freely swimming 
generation of medusse (II., IV., VI., etc.) This alteration of 
generation can only be explained by the Theory of Descent. 

The same remark applies to a kindred form of propagation, 
which is still more remarkable, and which I discovered in 1864, 
near Nice, in the Elephant-jellies (Geryonida), and called alloso- 
gony, or alloeo genesis. In this case two completely distinct forms 
of medusa arc descended from one another ; the larger and more 
highly developed generation (11), Geryonia, or Carmarina, is six- 
rayed, with six foliated sexual organs, and six very movable 
marginal filaments. Fi'om the centre of its bell-shaped cup, like 
the tongue of a bell, hangs a long proboscis, at the end of which 
is the opening of the mouth and stomach. In the cavity of the 
stomach is a long, tongue-shaped bunch of bnds (which on 
Plate VII. («) is extended from the month on the left like a 
tongue) . On this tongue, when the Geryonia is sexually ripe, 
there bud a nnmber of small medusiB. They are, however, not 
Geryonice, but belong to an entirely distinct but very different 
form of medusa, namely, to the genua Cunina, of the family of 
the JEginida. This Cunina (12) is very difCerently constructed; 
it has a flat, semi-globular cup without proboscis, consists in 
early life of six divisions, later of sixteen, and has siiteen bag- 
shaped sexual organs, and sixteen short, stiff, and strongly curved 
tentacles. A further explanation of this wonderful alloeogenesis 
may be found in my "■ Contributions to the Natural History of 
the HydromeduSK." (^Leipzig, Englemann, 1865), the first part 
of which contains a monograph of the Elephant-jellies, or 
Geryonida, illustrated by six copper-plates. 

Even more interesting and instructive than these remark- 
able relations are the vital phenomena of the Siplionopliora, 
whose wonderful polymorphism I have frequently spoken of 
and described in a popular manner in my lecture on " Diffcrentai- 


tion in Nature and Human Life." ^^ (Compare vol. i. p. 2/0, and 
vol. ii. p. 140). An example of this is given in Plate VII. in 
the drawing of the beautiful Physophora (13). This swimming 
stock or colony of hydromedusse is kept floating on the surface 
of the sea by a small swimming bladder filled with air, which in 
the drawing is seen rising above the sui'face of the water. Below 
it is a column of four pairs of swimming bells, which eject water, 
and thereby set the whole colony in motion. At the lower end of 
the column of swimming bells is a crown-shaped wreath of curved 
spindle-shaped sensitive polyps, which also serve as a cover- 
ing, under the protection of which the other individuals of the 
stock (the eating, catching, and reproductive persons) are 
hidden. The ontogenesis of the Siphonophora (and especially of 
this Physophora), I first observed in Lanzerote, one of the 
Canary Islands, in 18G6, and described in my " History of the 
Development of the Siphonophora," and added fourteen plates for 
its explanation. (Utrecht, 1869). It is rich in interesting facts, 
which can only be explained by the Theory of Descent. 

Another circumstance, which is also only explicable by the 
Theory of Descent, is the remarkable change of generation in the 
higher meduSEe, the disc-jellies (Discomedus®, vol. ii. p. 136), a 
representative of which is given at the top of Plate VII., in the 
centre (rather in the back ground), namely, a Pelagia (14). 
Prom the bottom of the bell-shaped cup, which is strongly arched 
and the rim of which is neatly indented, there hang four very 
long and strong arms. The non-sexual polyps, from which these 
disc-jellies are derived, are exceedingly simple primaeval polyps, 
difEering very little from the common fresh- water polyp (Hydra). 
The alternation of generation in these Discomedusas has also been 
described in my lecture on Differentiation,'' and there illus- 
trated by the Aurelia by way of example. 

Finally, the last class of Zoophytes, the group of comb- jellies 
(Ctenophora, vol. ii. p. 142), has two representatives on Plate VII. 
To the left, in the centre, between the ^quorea (9), the Phy- 
sophora (13), and the Cunina (12), is a long and thin band 
like a belt (15), winding like a snake ; this is the large and 



splendid Venus' girdle of tlie Mediterranean (Cestnm), tlie colours 
of whidi are as varied as those of the rainbow. The actual hody 
of the animal, which lies in the centre of the long belt, is very- 
small, and constructed exactly like that of the m.elon-jelly 
(Cydippe), which floats above to the left (16). On the latter are 
visible the eight characteristic fringed bands, or ciliated combs, 
of the ctenophora, and also two long tentacles which extend right 
across the page, and are fringed with still finer threads. 

Plates VIII. and IX. {Between ]]ages 170 and 171, Yol. II.) 

Hitiiory of the Vevelojnnent of Star-fishes (Echinoderma, or 
Estrella). The two plates exhibit their alternation of generation 
(vol, ii. p. 168), with an example from each of the four classes of 
Star-fishes. The sea-stars (Asterida) are represented by Uraster 
(4), the sea-lilies (Crinoida) by Comatula (£), the sea-urchins 
(Echinida) by Echinus ((7), and finally, the sea-cucumbers 
(Holothurioe) by Synapta (i*). (Compare vol. ii. pp. 166 and 176). 
The successive stages of development are marked by the numbers 

Plate VIII. represents the individual development of the first 
and non-sexual generation of Star-fishes, that is, of the nurses 
(usually, but erroneously, called larv»). These nurses possess 
the form.- value of a simple, nnsegmented worm-individual. Pig 1 
represents the egg of the four Star-fishes ; and it, in all essential 
points, agrees with that of man and of other animals. (Compare 
vol. i. p. 297, Pig. 5.) As in man, the protoplasm of the egg- 
cell (the yolk) is surrounded by a thick, structureless membrane 
(zona pellucida), and contains a globular, cell-kernel (nucleus), 
as clear as glass, which again encloses a nucleolus. Out of the 
fertilised egg of the Star-fish (Fig. A 1) there develops in the 
first place, by the repeated sub- division of cells, a globular mass 
of homogeneous cells (Pig. 6, vol. i. p. 299), and this changes into 
a very simple nurse, which has almost the same shape as a 
woodcu shoe (Pig. A 2 — T) 2). The edge of the opening of the 
shoe is bordered by a fringe of cilia, the ciliary movements of 


wliicli keep tlie microscopically small and transparent nui-se 
swimming about freely in the sea. This fringe of cilia is marked 
in Pig A 2 — A 4, on Plate VII., by the narrow alternately light 
and dark seam. The nnrse then, in the first place, forms a per- 
fectlyslmple intestinal canal for nutrition, month (0), stomach (m) 
and anus (a). Later, the windings of the fringe of cilia become 
more complicated, aud there arise arm-like processes (Fig. A 3 — 
D3). In sea-stars (Ai} and sea-urchins (0 4) these arm- 
like processes, which are fringed with cilia, afterwards become 
very long. But in the case of sea-lilies (B 3) and sea-cucumbers 
(D 4), instead of this, the fringe of cilia, which at first, through 
winding in and out, forms one closed ring, changes subsequently 
into a succession of separate ciliated girdles, one lying behind 
the other. 

In the interior of this curious nurse there then develops, by 
a non-sexual process of generation, namely, by the formation of 
internal buds or germ-buds (round about the stomach), the 
second generation of Star-fishes, which later on become sexually 
ripe. This second generation, which is represented on Plate 
IX. in a fully developed condition, exists originally as a stock 
or cormiis of five worms, connected at one end in the form 
of a star, as is most clearly seen in the sea-stars, the most 
ancient and original fonn of the star-fishes. The second 
generation, which grows at the expense of the first, appropriates 
only the stomach and a small portion of the other organs of the 
latter, but forms for itself a new mouth and anus. The fringe of 
cilia, and the other parts of the body of the nurse, afterwards dis- 
appear. The second generation {A 5 — D 5), is at first smaller or 
not much larger than the nurse, whereas, by growth, it afterwards 
becomes more than a hundred times, or even a thousand times, as 
large. If the ontogeny of the typical representatives of the 
four classes of Star-fishes be compared, it is easily seen that 
the original kind of development has been best preserved in 
sea-stars {A) and sea-urchins (C) by inheritance, whereas in 
sea-lUies (B) and sea-cucumbers it has been suppressed accord- 
ing to the laws of abbreviated inheritance (vol, i. p. 212). 


Plate IX. sliows the fully developed and sexually mature 
animals of the second generation from the month side, which, in. 
the natural position of Star-fishes (when creeping at the bottom 
of the sea), in sea-stars {A C) and sea-urchins (0 6), is below, 
in sea-lilies {B 6) above, and in sea-cucumbers (7) 6) in front. 
In the centre we perceive, in all the four Star-fishes, the star- 
shaped, five-pointed opening of the mouth. In sea-stars, from 
each arm there extend several rows of little sucking feet, from 
the centre of the nnder-side of each arm to the end. In sea- 
lilies (_B 6), each arm is split and feather-like from its base up- 
wards. In sea-urchins (C 6) the five rows of sucking feet are 
divided by broader fields of spines. In sea-cucumbers, lastly 
(D 6), on the worm-like body it is sometimes only the five rows 
of little feet, sometimes only the feathery tentacles surrounding 
the month, from five to fifteen (in this case ten), that are exter- 
nally visible. 

(Plates X. and XI. (Between pages 174 and 175, Vol. II.) 

Historical Development of ilie Grah-flsJi (Crustacea). — The two 
plates illustrate the development of the diffei'ent Crustace.i from 
the nauplins, their common primreval form. On Plate XI. six 
Crustacea, from six different orders, are represented in a fully 
developed state, whereas on Plate X. the early nauplins stages are 
given. From the essential agreement between the latter we may, 
on the ground of the fundamental law of biogeny, with full 
assurance maintain the derivation of the different Crustacea 
from a single, common primary form, a long since extinct 
Nauplins, as was first shown by Fritz Miiller in his excellent 
work " Fiir Darwin." '* 

Plate X. represents the eai-lij nauplins stages from the ventral 
side, so that the three pairs of legs, on the short, three- jointed 
trunk are distinctly visible. The first of these pairs of legs is 
simple and nnsegmented, whereas the second and third pairs 
are forked. All three pairs are furnished with stiff bristles, 
which, through the paddling motion of the legs, serve as an 
apparatus for swimming. In the centre of the body, the per- 


fectly simple, straight intestinal canal is visible, possessing a 
moTith in front, and an anal orifice behind. In front, above the 
month, lies a simple, single eye. All the six forms of nauplius 
entirely agree in all these essential characteristics of organiza- 
tion, whereas the six fully developed forms of Crustacea belong- 
ing to them, Plato XI., are extremely different in organisation. 
The differences of the six nauplius forms are confined to quite 
subordinate and unessential relations in regard to size of body, 
and the formation of the covering of the skin. If they could 
be met with in this form in a sexually mature condition, no 
zoologist would hesitate to regard them as six different species 
of one genus. (Compare vol. ii. p. 175.) 

Plate XI. represents those fully developed and sexually mature 
forms of Crustacea, as seen from the right side, which have 
ontogenetically (hence also phylogenetically) developed out 
of the six kinds of nauplius. Pig. A c shows a freely swim- 
ming fresh-water crab (Limnetis brachyurus) from the order of 
the Leaf-foot Crabs (Phyllopoda), slightly enlarged. Of all the 
still living Crastacea, this order, which belongs to the legion of 
Gill-foot Crabs (Branchiopoda), stands nearest to the original, 
common primary form of nauplius. The Limnetis is enclosed in 
a bivalved shell, like a mussel. Our drawing (which is copied 
from Grube) represents the body of a female animal lying in the 
left shell ; the right half of the shell has been removed. In 
front, behind the eye, we see the two feelers (antennas), and 
behind them the twelve leaf-shaped feet of the right side of the 
body, behind on the back (under the shell), the eggs. Above, iu 
front, the animal is fixed to the shell. 

Pig. B c represents a common, freely swimming fresh-water 
crab (Cyclops quadricornis) from the order of Oar-legged crabs 
(Bucopepoda), highly magnified. In front, below the eye, we 
see the two feelers of the right side, the foremost of which is 
longer than the hinder one. Behind these are the gills, and 
then the four paddling legs of the right side. Behind these are 
the two large egg-sacks, which, in this case, are attached to the 
end of the hinder part of the body. 


Fig. c is a parasitic Oar-leggcd crab (Lemaeocera esooina), 
from the order of fish, lice (Siphonostoma). These peculiar 
crabs, which were formerly regarded as worms, have originated, 
by adaptation to a parasitical life, out of freely swimming, Oar- 
legged crabs (Eucopepoda), and belong to the same legion 
(Copepoda, vol. ii. p. 176). By adhering to the gills on the skin of 
fish or other crabs, and feeding on the juice of these creatures, 
they forfeited their eyes, legs, and other organs, and developed 
into formless, inarticulated sacks, which, on a mere external 
examination, we should never suppose to be animals. On the 
ventral side only there exist, in the shape of short, pointed 
bristles, the last remains of legs which have now almost entirely 
disappeared. Two of these rudimentary pairs of legs (the third 
and fourth) are seen in our drawing on the right. Above, ou 
the head, we see thick, shapeless appendages, the lower ones of 
which are split. In the centre of the body is seen the intestinal 
canal, which is surrounded by a dark covering of fat. At 
its posterior end is the ovary, and the cement-g]ands of the 
female sexual apparatus. The two large egg-sacks hang ex- 
ternally (as in the Cyclops, Fig. B). Our Lernoeocera is 
represented in half profile, and is copied from Clans. (Compai'c 
Claus, " Die Copepoden-Fauna von Nizza. Ein Beitrag zur 
Characteristik der Formen und doren Abanderungen im Sinne 
Darwins." Marburg, 18G6). 

Fig. D c represents a so-called "duck m.ussel" (Lepas 
anatifera), from the order of the Barnacle crabs (Cirripedia)- 
These crabs, upon which Darwin has written a very careful 
monograph, are, like mussels, enclosed in a bivalved, calcareous 
case, and hence were formerly (even by Cuvier) universally 
regarded as a kind of mussel, or mollusc. It was only from a 
knowledge of their ontogeny, and their early nauplius form (J> n, 
Plate VIII.), that their crustacean nature was proved. Our 
drawing shows a "duck mussel " of the natural size, from the right 
side. The right half of the bivalved shell has been removed, so 
that the body is seen lying in the left half of the shell. From 
the rudimentary head of the Lepas there issues a long, fleshy 


stalk (curving upwards in onr drawing) ; hj means of it the 
Barnacle crab grows on rocks, ships, etc. On the ventral side are 
six pairs of feet. Every foot is forked and divided into two 
long, curved, or curled " tendrils " furnished with bristles. 
Above and behind the last pair of feet projects the thiu cylin- 
drical tail. 

Fig. E c represents a parasitic sack-crab (Sacculina purpurea) 
from the order of Eoot-crabs (Rhizocephala). These parasites, 
by adaptation to a parasitical life, have developed out of Barnacle 
crabs (Fig. D c), much in the same way as the fish-lice (C c), 
out of the freely swimming Oar-legged crabs (U c). However, 
the suppression, and the subsequent degeneration, of all of the 
organs, has gone much further in the present case than in most 
of the fish-lice. Out of the articulated crab, possessing legs, 
intestine, and eye, and which in an early stage as nauplius (.B m, 
Plate VIII.), swam about freely, there has developed a formless, 
unsegmented sack, a red sausage, which now only contains 
sesual organs (eggs and sperm) and an intestinal rudiment. The 
legs and the eye have completely disappeared. At the posterior 
end is the opening of the genitals. From the mouth grows a 
thick bunch of numerous tree-shaped and branching root-like 
fibres. These spread themselves out (like the roots of a plant 
in the ground) in the soft hinder part of the body of the hermit- 
crab (Pagurus), upon which the root-crab lives as a parasite, and 
from which it draws its nourishment. Oar drawing (^ c), a 
copy of Fritz Miiller's, is slightly enlarged, and shows the whole 
of the sausage-shaped sack-crab, with aU its root-fibres, when 
di-awn out of the body upon which it lives. 

Fig. i*" c is a shriinp (Peneus Miilleri), from the order of ten-foot 
crabs (Decapoda), to which our river cray-fish, and its nearest 
relative, the lobster, and the short-tailed shore-crabs also belong. 
This order contains the largest and, gastronomically, the most im- 
portant crabs, and belongs, together with the mouth-legged and 
split-legged crabs, to the legion of the stalk-eyed mailed crabs 
(Podophthalma). The shrimp, as well as the river crab, has in 
front, on each side below the eye, two long feelers (the first 


much shorter than the second), then three jaws, and three jaw- 
feet, then five very long legs (the three fore ones of which, in 
the Penens, are furnished with nippers, and the third of which is 
the longest). Finally, on the first five joints of the hinder part 
of the body there are other five pairs of feet. This shrimp, 
which is one of the most highly develojied and perfect crabs, 
originates (according to Fritz Miiller's important discovery) out 
of a nauplius (_F n Plate VIII.), and consequently proves that 
the higher Crustacea have developed out of the same form 
as the lower ones, namely, the nauplius. (Compare voL ii. p. 176). 

Plates XII. anb XIII. {Between pages 200 and, 201, Vol. II.) 

Blood relaiionsMp hehveen ihe Veriehrata and the Inveriehrata. 
(Compare vol. ii. pp. 152 and 201.) It is definitely estabHshed 
by Kowalewski's important discovery, which was confirmed by 
Kupflier, that the ontogeny of the lowest vertebrate animal — the 
Lancelet, or Amphioxus — agrees in all essential outlines com- 
pletely with that of the invertebrate Sea-squirts, or Ascidia?, 
from the class of Sea-sacks, or Tunicata. On our two plates, 
the ascidia is marked by A, the amphioxus by B. Plate XIII. 
represents these two very different animal-forms in a fully 
developed state, as seen from the left side, the end of the mouth 
above, the opposite end below. Hence, in both figures the dorsal 
side is to the right, the ventral to the left. Both figures &ve 
slightly magnified, and the internal organisation of the animals 
is distinctly visible through the transparent skin. The full- 
grown ascidia (Pig. A 6) gi'ows at the bottom of the ocean, 
from whence it cannot move, and clings to stones and other 
objects by means of peculiar roots (w) like a plant. The full- 
grown amphioxus, on the other hand (Fig. B 6), swims about 
freely like a small fish. The letters on both figures indicate the 
same parts : (a) orifice of the mouth ; (6) orifice of the body, or 
porus abdominalis ; (c) dorsal rod, or chorda dorsalis ; (d) intes- 
tine ; (e) ovary ; (/) oviduct (same as the sperm-duct) ; (g) spinal 
marrow t (h) heart; (i) blind-sao of the intestine; (le) giU 


basket (respiratory cavity) ; (I) cavity of tlie body ; (m) muscles ; 
(n) testicle (in the ascidia united witt the ovary into a herma- 
pbrodite gland) ; (o) anus ; (p) genital orifice ; (g) well-developed 
embryos in the body cavity of tbe ascidia; (r) rays of tlie 
dorsal fin of the amphioxus ; (s) tail-fin of the amphioxus ; (zv) 
roots of the ascidia. 

Plate XII. shows the Ontogenesis, or the individual development 
of the Ascidia {A) and the A'npliioxus (U) in five different 
stages (1-5). Fig. 1 is the egg, a simple cell like the egg of 
man and all other animals (Fig. A 1 the egg of the ascidia, Fig. 
B 1 the egg of the amphioxus). The actual cell-substance, or 
the protoplasm of the egg-cell (z), the so-called yolk, is sur- 
rounded by a covering (cell-membrane, or yolk-membrane), 
and encloses a globular cell-kernel, or nucleus (y), the latter, 
again, contains a kernel-body, or nucleolus (a;) ; when the egg 
begins to develop, the egg-cell first subdivides into two cells. 
By another sub-division there arise four cells (Fig. A2, B 2), and 
out of these, by repeated sub-division, eight cells (vol. i. p. 190, 
Fig. 4 G, D). By 11 aid gathering in the interior these form a 
globular bladder bounded by a layer of cells. On one spot of its 
surface the bladder is turned inwards in the form of a pocket (Fig. 
A 4<, B 4), This depression is the beginning of the intestine, 
the cavity (d 1) of which opens externally by the provisional 
larval-mouth {d 4). The body-wall, which is at the same time 
the stomach-wall, now consists of two layers of cells — the 
germ-layers. The globular larva (Gastrula), now grows in 
length. Fig. A 5 represents the larva of the ascidia. Fig. B 6 
that of the amphioxus, as seen from the left side in a somewhat 
more advanced state of development. The orifice of the intestine 
(d 1) has closed. The dorsal side of the intestine (d 2) is con- 
cave, the ventral side (d 3) convex. Above the intestinal tube, 
on its dorsal side, the neural tube, the beginning of the spinal 
m.arrow, is being formed, its cavity still opens externally in front 
(g 2). Between the spinal marrow and the intestine has arisen 
the spinal rod, or chorda dorsalis (Notochord) (c), the axis of the 
inner skeleton. In the lai'va of the ascidia this rod (c) proceeds 


along tlie long rudder-tail, a larval organ, wMch is cast off 
in later transformation. Yet there still exist some very small 
ascidise (Appendicnlaria) wliicli do not become transformed 
and attaclied, but which through life swim about freely in the 
sea by m.eans of their rudder-tail. 

The ontogenetic facts which are systematically represented on. 
Plate XII. and which were first discovered in 1867, deserve the 
greatest attention, and, indeed, cannot be too highly estimated. 
They fill up the gap which, according to the opinion of older zoolo- 
gists existed between the vertebrate and the so-called " inverte- 
brate " animals. This gap was universally regarded as so im- 
portant and so undeniable, that even eminent zoologists, who 
were not disinclined to adopt the theory of descent, saw in this 
gap one of the chief obstacles against it. Now that the ontogeny 
of the amphioxus and the ascidia has set this obstacle completely 
aside, we are for the first time enabled to trace the pedigree of 
man beyond the amphioxus into the many-branching tribe of 
"invertebrate " worms, from which all the other higher animal 
tribes have originated. 

If our speculative philosophers. Instead of occupying them- 
selves with castles in the air, were to give their thoughts for some 
years to the facts represented on Plates XII. and XIII., as well 
as to those on Plates II. and III., they would gain a foundation 
for true philosophy — for the knowledge of the universe firmly 
based on experience — which would be sure to influence all 
regions of thought. These facts of ontogenesis are the in- 
destructible foundations upon which the monistic philosophy 
of future times will erect its imperishable system, 

Plate XIV. (Between pages 206 and 207, Vol. 11.) 

Monojpliyletic, or One-rooted Pedigree of tlie Verteirate Animal 
tribe, representing the hypothesis of the common derivation of 
all vertebrate animals, and the historical development of their 
different classes during the palasontological periods of the earth's 
history. (Compare Chapter XX. vol. ii. p. 192.) The horizontal 


lines indicate the periods (mentioned in vol. ii. p. 14) of tlic organic 
history of the earth during which the deposition of the strata con- 
taining fossils took place. The vertical lines separate the classes 
and sub-classes of vcrtehrata from one another. The tree-shaped 
and hranching lines, by their greater or lesser number and thick- 
ness, indicate the approsimate degree of development, variety, and 
perfection, which each class probably attained in each geological 
period. In those classes which, on account of the soft nature of 
their bodies, could not leave any fossil remains (which is especially 
the case with Prochordata, Acrania, Monorrhina, and Dipneusta) 
the course of development is hypothciically suggested on the 
ground of arguments derived from the three records of creation 
— comparative anatomy, ontogeny, and palaeontology. The 
most important starting-points for the hypothetical completion 
of the palreontological gaps are here, as in all cases, furnished 
by the fundaimental law of biogeny, which asserts the inner ca/usal- 
nexus existing between ontogeny and phylogeny. (Compare vol. i. 
p. 310, and vol. ii. p. 200 ; also Plates VIII.— XIII.) In all cases 
we have to regard the individual development (determined by the 
laws of Inheritance but modified by the laws of Adaptation) as 
short and quick repetitions of the paloeontological development 
of the tribe. This proposition is the " ceteram censeo " of our 
theory of development. 

The statements of the first appearance, or the period of the 
origin of the individual classes and sub-classes of vertebrate 
animals (apart from the hypothetical filling in mentioned just 
now), are taken as strictly as possible from palseontological 
facts. It must, however, be observed, that in reality the origin 
of most of the groups probably took place pne or two periods 
earlier than fossils now indicate. In this I agree with Huxley's 
views ; but on Plates V. and XIV. I have disregarded this con- 
sideration in order not to go too far from patoontological facts. 

The numbers signify as follows (compare also Chapter XX. and 
vol. ii. pp. 204, 206) : — 1. Animal Monera ; 2. Animal Amcebse ; 
3. Community of Amoebae (Synamoebae) ; 4. Ciliated Infusoria 
without mouths ; 5. Oihated Infusoria with mouths ; 6. Gliding 


worms (Turbellaria) ; 7. Sea-sacks (Tnnicata) ; 8. Lancelet 
(AmpTiioxus) ; 9. Hag (Myxinoida) ; 10. Lamprey (Petro- 
myzontia) ; 11. Unknown forms of transition from single- 
nostriled animals to primajval fislies; 12. Silurian primseval 
fisk (Onclius, etc.); 13. Living primaeval fiskes (skarks, rays, 
Chimasrffi) ; 14. Most ancient (Silurian) enamelled fiskes 
(Pteraspis); 15. Turtle fiskes (Pampkracti) ; 16. Sturgeons 
(Sturiones) ; 17. Ajigular-scalcd enamelled fiskes (Rkom- 
biferi) ; 18. Bony pike (Lepidosteus) ; 19. Finny pike (Polyp- 
terus) ; 20. Hollow-boned fiskes (Creloscolopes) ; 21. Solid boned 
fiskes (Pycnoscolopes) ; 22. Bald pike (Amia) ; 23. PrimEeval 
boned fiskes (Thrissopida) ; 24. Bony fiskca witk air passage 
to tke swimming bladder (Pkysostomi) ; 25. Bony fiskea witb- 
out air passage to tke swimming bladder (Physoclisti) ; 26. 
Unknown forms of transition between prima3val fiskes and 
ampkibious fiskes ; 27. Ceratodus ; 27a. Extinct Ceratodus from 
tke Trias ; 276. Living Australian Ceratodus ; 28. African 
ampkibious fiskes (Protopterus) and American ampkibious fiskes 
(Lopidosiren) ; 29. Unknown forms of transition between primse- 
val fiskes and ampkibia ; 30. Enamelled beads (Ganocepkala) ; 
31. Labyrintk tootked (Labyrintkodonta) ; 32. Blind burrowers 
(Cseoilise) ; 33. Gilled ampkibia (Sozobranckia) ; 34. Tailed 
ampkibia (Sozura) ; 35. Frog ampkibia (Anura) ; 36. Dick- 
tkacantka (Proterosaurus) ; 37. Unknown forms of ti-ansition 
between Ampkibia and Protamnia; 38. Protamnia (common 
primary form of all Amnion animals) ; 39. Primary mam- 
mals (Promammalia) ; 40. PrimEeval reptiles (Proreptilia) ; 41. 
(Thecodontia) ; 42. Primseval dragons (Simosauria) ; 48. Ser- 
pent dragons (Plesiosauria) ; 44. Fisk dragons (Ickthyosauria) ; 
45. Teleosauria (Ampkicoela) ; 46. Steneosauria (Opistkocoela) ; 
47. Alligators and Crocodiles (Prostkocoela) ; 48. Carnivorous 
Dinosauria (Harpagosauria) ; 49. Herbivorous Dinosauria (Tkero- 
eauria); 60. Msestrickt lizards (Mosasauria) ; 51. Common primary 
form of Serpents (Opkidia) ; 52. Dog-tootkcd beaked lizards 
(Cynodontia) ; 53. Tootkless beaked lizards (Cryptodontia) ; 
54. Long-tailed flying lizards (Rkampkorkyncki) ; 55. Skort-taUed 


flying lizards (Pterodactyli) ; 56. Land tortoises (Chersita) ; 
67. Birds — ^reptiles (Tocornithes), transition form between 
reptiles and birds ; 68. Primaeval griffin (ArcheBopteryx) ; 59. 
Water beaked-animal (Omitliorhynelius); 60. Land beaked-animal 
(Echidna) ; 61. Unknown forms of transition between Cioa- 
cals and Marsupials ; 62. Unknown forms of transition 
between Marsupials and Placentals ; 63. Tuft Placentals (Villi- 
placentalia) ; 64. Girdle Placentals (Zonoplacentalia) ; 65. Disc 
Placentals (Discoplacentalia) ; 66. Man (Homo pithecogenes, by 
Linnaeus erroneously called, Homo sapiens.) 

Plate XV. (After page 369, Vol. II.) 

Eypothetical Sketch of the Monopliyletic Origin and tJie Diffusion 
of the Twelve Species of Men from Lemuria over the earth. The 
hypothesis here geographically sketched of course only claims an 
entirely provisional value, as in the present imperfect state of our 
anthropological knowledge it is simply intended to show how 
the distribution of the human species, from a single primaeval 
home, may be approximately indicated. The probable primasval 
home, or " Paradise," is here assumed to be Lemuria, a tropical 
continent at present lying below the level of the Indian Ocean, 
the former existence of which in the tertiary period seems very 
probable from numerous facts in animal and vegetable geography. 
(Compare vol. i. p. 361, and vol. ii. p. 315.) But it is also very 
possible that the hypothetical " cradle of the human race " lay 
further to the east (in Hindostan or Further India), or further to 
the west (in eastern Africa). Future investigations, especially in 
comparative anthropology and pateontology, wUl, it is to be hoped, 
enable us to determine the probable position of the primseval 
home of man more definitely than it is possible to do at present. 

If in opposition to our monophyletic hypothesis, the polyphyletic 
hypothesis — which maintains the origin of the different human 
species from several different species of anthropoid ape — be pre- 
ferred and adopted, then, from among the many possible hypo- 
theses which arise, the one deserving most confidence seems to bo 


that whicli assumes a double pitliecoid root for tlie Iniman race 
namely, an Asiatic and an African root. Foi' it is a very remark- 
able fact, that the African man-like apes (gorilla and chim- 
panzee) are characterized by a distinctly long-headed, or 
dolichocephalous, form of skull, like the human species peculiar 
to Africa (Hottentots, Caffres, Negroes, Nubians). On the other 
hand, the Asiatic man-like apes (especially the small and large 
orang), by their distinct, short-headed, or brachyccphalous, form 
of skull agree with human species especially characteristic of 
Asia (Mongols and Malays). Hence, one might be tempted to 
derive the latter (the Asiatic man-like apes and primreval men) 
from a common form of brachyccphalous ape, and the former 
(the African man-like apes and primoeval men) from a common 
dolichocephalous form of ape. 

In any case, tropical Africa and southern Asia (and between 
them Lemuria, which formerly connected them) are those 
portions of the earth which deserve the first consideration in 
the discussion as to the primsBval home of the human race ; 
America and Australia are, on the other hand, entirely excluded 
from it. Even Europe (which is in fact but a western peninsula 
of Asia) is scarcely of any importance in regard to the " Paradise 

It is self-evident that the migrations of the different human 
species from their primasval home, and their geographical distri- 
bution, could on our Plate XV. be indicated only in a very 
general way, and in the roughest lines. The numerous migrations 
of the many branches and tribes in all directions, as well as the 
very important re-migrations, had to be entirely disregarded. In 
order to make these latter in some degree cleai", our knowledge 
would, in the first place, need to be much more complete, and 
secondly, we should have to make use of an atlas with a number 
of plates showing the various migrations. Our Plate XV. claims 
no more than to indicate, in a very general way, the approximate 
geographical dispersion of the twelve human species as it existed 
in the fifteenth century (before the general diffusion of the Indo- 
Germanic race), and as it can be sketched out approximately, 


so as to harmonize with our hypothesis of descent. The geo- 
graphical barriers to diffusion (mountains, deserts, rivers, straits, 
etc.), have not been taken into consideration in this general 
sketch of m.igration, because, in earlier periods of the earth's 
history, they were quite different in size and form from what 
they are to-day. The gradual transmutation of catarrhine apes 
into pithecoid men probably took place in the tertiary period in 
the hypothetical Lemnria, and the boundaries and forms of the 
present continents and oceans must then have been completely 
different from what they are now. Moreover, the mighty in- 
fluence of the ice period is of great importance in the question 
of the migration and diffusion of the human species, although 
it as yet cannot be more accurately defined in. detail. I here, 
therefore, as in my other hypotheses of development, expressly 
guard myself against any dogmatic interpretation; they are 
nothing hut first attempts. 



Abtssinians, ii. 323, 330 
AcalephsB, ii. 141 
Acoelomi, ii. 148, 151 
Aorania, ii. 196, 198, 200, 204 
Aoyttaria, ii. 51, 62 
Adaptation, i. 90, 156, 219 

actual, i. 225, 231 

correlative, i. 241 

cumulative, i. 233 

direct, i. 225, 231 

divergent, i. 247 

indirect, i. 224, 227 

individual, i. 228 

irregular, i. 229 

monstrous, i. 229 

potential, i. 224, 227 

■ — sexual, i. 230 

universal, i. 231 

unlimited, i. 249 

Agassiz, Louis, i. 61 

Agassiz's conception of the universe, 
i. 65 

essay on classification, i. 61 

history of creation, i. 63 

history of development, 

i. 64 

idea of species, i. 65 

Albuminous bodies, i. 331 
Algse, ii. 81, 82, 83 
Alluvial system, ii. 15 
Altaians, ii. 309, 317 
Alternation of generations, i. 20G 
Americans, Ii. 309, 318. 
Amnion animals, ii. 204, 219 
Amniota, ii. 204, 219 
Amoabse, ii. 53, 279 
Amoeboidea, ii. 53 
Amphibia, ii. 209, 216 
Amphioxua, ii. 198, 285 
Amphirrhina, ii. 203, 205 
Anamnionata, ii. 204 
Animal Plants, ii. 144 
Angiospermaj, ii. 83, 111 

Annelida, ii. 133, 149, 151 
Anorgana, i. 5, 328 
Anorganology, i. 6 
Anthozoa, ii. 143 
Anthropocentrio conception of the 

universe, i. 38 
Anthropoides, ii. 270, 275, 292 
Anthropolithic period, ii. 15, 17 
Anthropology, i. 7 
Anthropomorphism, i. 18, 6G 
Ape-liko men, ii. 293, 300 
Apes, ii. 241, 268, 270 
Arabians, ii. 323, 330 
Arachnida, ii. 180, 182 
Archelminthes, ii. 148 
Archezoa, ii. 132, 134 
Arohigony, i. 183, 338 
Archilithic period, ii. 8, 14 
Arians, ii. 323, 331 
Aristotle, i. 55, 76 
Arthropoda, ii. 132 
Articulata, ii. 119 
Ascidia, ii. 162, 200 
Ascones, ii. 141 
Asterida, ii. 164, 166 
Atavism, i. 207 
Australians, ii. 308, 314 
Autogeny, i. 339 

Bae, Caul Erkst, i. 109 

doctrine of filiation, i. 109 

theory of development, i. 294 

types of animals, i. 53 ; ii. 119 

Basques, ii. 322 

Bathybius, i. 184, 344 ; ii. 53 

Batrachians, ii. 204 

Bats, ii. 240, 261 

Beaked mammals, ii. 233, 239 

■ reptiles, ii. 224, 226 

Belief, i. 9 ; ii. 335 
Berbers, ii. 323, 330 
Biogenesis, fundamental law of, i. 
309 ; ii. 33 



Eiology, i. 6 

Birds, ii. 204, 226 

Braohiopoda, ii. 157 

Brain, bladder of, in man, i. 304 

development of, i. 303 

Bruno Giordano, i. 22, 70 
Bryozoa, ii. 160, 152 
Buch, Leopold, i. 107 
Biichner, Louis, i. 110 
Buds, formation of, L 192 


Caffkes, ii. 312, 333 
Calcispongiae, ii. 140, 144 
Cambrian system, ii. 9, 15 
Carbon, i. 330, 335 

theory of, i. 335 

Carboniferous system, ii. 11, 15 

Carus Victor, i. 110 

Catallacta, i. 51, 59 

Catarrhini, ii. 270, 272 

Caucasians, ii, 809, 321 

Causa finalis, i. 34, 75 

Causal eouception of the universe, 

i. 18, 74 
Cells, i. 187, 346 

formation of, i. 347 

■ theory of, i. 346 

Cell-kernel, i. 188 

membrane, i. 188 

substance, i. 186 

Csenolithic period, ii. 14, 16 
Cephalopoda, ii. 160, 162 
Chamisso, Adalbert, i. 206 
Change of climate, i. 363 
Chelophora, ii., 240, 257 
Chinese, ii. 309, 317 
Chorology, i. 351 

Cloacal animals, ii. 234, 239 
Cochlides, ii. 159, 160 
Ccelenterata, ii. 136, 144 
Coelomati, ii. 148, 151 
Coniferas, ii. 82, 110 
Constructive forces, L 90, 253, 337 
Copernicus, i. 39 
Corals, ii. 142, 144 
Coreo-Japanese, ii. 309, 317 
Cormophytes, ii. 80 
Correlation of parts, i. 218 
Cosmogeny, i. 321 
Cosmological gas theory, i. 323 
Crabs, ii. 174, 176 

Craniota, ii. 198, 204 
Creation, centres of, i, 352 

the, i. 8 

Creator, the, i. 64, 70 
Cretaceous system, u. 12, 15 
Crinoides, ii. 166, 171 
CrocodUes, ii. 223, 224 
Crustacea, ii. 173, 176 
Cryptogamia, ii. 80, 82 
Ctenophora, ii. 142, 144 
Cultivated plants, i. 137 
Curly-haired men, ii. 310, 333 
Cuttles, ii. 160, 162 
Cuvier, George, i. 50 
Cuvier's dispute with Geoffroy, i. 88 

history of creation, i. 59 

palasontology, i. 54 

idea of species, i. 50 

■ — theory of cataclysms, i. 58 

theory of revolutions, i. 58 

types of animals, i. 53 ; ii. 118 

Cycadese, ii. 82, 110 
Cyclostoma, ii. 202, 204 
Cytod, i. 346 


Darwik Charles, i. 131 
Darwinism, i. 149 
Darwin's life, i. 132 

travels, i. 132 

theory of corals, i. 133 

theory of selection, i. 150 

study of pigeons, i. 141 

Darwin, Ersismus, i. 118 
Deoiduata, ii. 240, 255 
Deduction, i. 85 ; ii. 357 
Demooritus, i. 22 
Devonian system, ii. 11, 14 
Diatomea), ii. 51, 60 
Diootylse, ii. 82, 112 
Didelphia, ii. 239 
Differentiation, i. 270, 283 
Diluvial system, ii. 15 
Dipneusta, ii. 204, 212 
Divergence, i. 270 
Division of labour, i. 247 
Domestic animals, i. 137 
Dragons, ii. 225 
Dravidas, ii. 308, 319 
Dualistic conception of the universe, 

i. 20, 75 
Dysteleology, i. 15; ii. 353 




EOHINIDA, ii. 1U6, 171 

Encliinoderma, ii. 103, 166 

Edentata, ii. 240, 251 

Egg Animals, ii. 132, 134 

Eggs, i. laO, 198 

Egg of man, i. IDO, 207 ; ii. 279 

Egg, cleavage of the, i. 190, 299 ; ii. 

Egyptians, ii. 323, 330 
Elephants, iL 257 
Empiricism, i. 79 ; ii. 3i9 
Eocene system, ii. 15, 16 
Ethiopians, ii. 323, 330 
Explanation of phenomena, i. 29 

Feens, ii. 82, 101 
Fibrous plants, ii. 82 
Final cause, i. 22 
Fins, ii. 309, 317 
Fishes, ii. 206, 208 
Flagellata, ii. 61, 57 
Flat-nosed apes, ii. 270, 272 
Flat worms, ii. 148, 150 
Flint cells, ii. 51, 60 
Flowering plants, ii. 82, 108 
Flower animals, ii. 143 
Flowerless plants, ii. SO, 82 
Flying animals, ii. 240, 2G1 
Freke, i. 119 
Fulatians, 11. 308, 320 
Fungi, ii. 82 


■ Ganoid fish, ii. 208, 210 
Gastraca, ii. 127, 128, 281 
Gastrula, ii. 126, 127 
Gegenbaur, i. 312; ii. 179, 193 
Gemmation, i. 192 
Generation, i. 209 
Oeniis, i. 41 

Geocentric conception of the uni- 
verse, i. 38 
Geofi'roy S. Hilairc, i. 86, 116 
Germans, ii. 323, 331 
Germ buds, formation of, i. 193 

■ cells, formation of, i. 194 

Gibbon, ii. 270, 275 
Gilled insects, ii. 174, 176 
Gill-ai'ches in man, i. 307 

God, conception of, i. 70 

Goethe, Wolfgang, i. 80 

Goethe's conception of nature, i. 22 

discovery of mid-jaw bone, 

i. 84 
formative tendency L 91, 


idea of God, i. 71 

investigations in nature, 


materialism, i. 23 

metamorphosis, i. 90 

metamorphosis of plants, 

i. 82 

philosophy of nature, i, 81 

theory of development, 

i. 92 

vertebra; of skull, i. 83 

Genochoristus, i. 196 
Gonochorism, i. 196 
Gorilla, ii. 270 
Grant, i. H§ 
Greeks, ii. 323, 331 
Gregarinoe, ii. 133, 134 
Gymnosperms, ii. 82, 109 


Halisacria, ii. 204, 214 
Hare-rabbit, i. 148, 275 
Heliozoa, ii. 64 
Herbert, i. 119 
Heredity, i. 176 
Hermaphrodites, i. 196 
Herschel's cosmogeny, i. 321 
Holothuriaj, ii. 166, 172 
Hoofed animals, ii. 249, 252 
Hooker, i. 119 
Hottentots, ii. 311, 333 
Human races, ii. 296, 305, 308 

soul, ii. 361 

Huxley, i. 119, 145 ; ii. 208 
Hybridism, i. 145, 210, 275 
Hydromedusse, ii. 143, 145 

Ice period, i. 307 ; ii. 17 
Indecidua, ii. 241, 249 
Individual development, Ii. 293 
Indo-Chinese, ii. 309, 317 
Indo-Germauic, ii. 323, 331 
Induction, i. 85, ii. 357 
Infusoria, ii. 132, 135 
Inheritance, abridged, i. 212 



Inheritance, acquired, i. 213 

adapted, i. 213 

amphigonous, i. 210 

ooneervatiTe, i. 204 

constituted, i. 216 

contemporaneous, i. 217 

- — continuous, i. 205 

established, i. 216 

homochronous, i. 217 

Interrupted, i. 205 

_ latent, i. 205 

mixed, 1. 210 

progiessive, i. 213 

■ sexual, i. 209 

simplified, i. 212 

• uninterrupted, 1. 205 

— laws of, i. 20 i 

Inophyta, ii. 82, 93 

Insects, ii. 184 
Inseotivora, ii. 24:1, 259 
Instinct, ii. 343 
Invertebrata, ii. 118, 195 
Iranians, ii. 323, 331 

Japanese, ii. 309, 317 
Jews, ii. 323, 330 
Jura system, ii. 12, 14 

Kant, Immantjel, i. 101, 321 
Kant's Criticism of the faculty of 
judgment, i. 105 

mechanisms, 1. 37, 102 

philosophy of nature, i. 101 

theory of descent, i. 103 

theory of development, i. 321 

theory of the formation of 

the universe, i. 101 
Knowledge, a posteriori, i. 31 ; ii. 345 
. a priori, i. 31 ; ii. 344 

Lacertilia ii. 223 
Lamarck] Jean, i. Ill 
Lamarck's anthropology, i. 115 ; 

ii. 264 
philosophy of nature, 

i. 112 

theory of descent, i. 113 

Lamarckism, i. 150 
LameUibranchia, ii. 158, 160 

Lanoelet, ii. 198, 204, 285, 
Laplace's cosmogony, i. 321 
Laurentian system, ii. 9, 14 
Lemuria, i. 361, ii. 326 
Leonardo da Vinci, i. 56 
Leptocardia, ii. 196, 204 
Leucones, ii. 141 
LinniBus, Charles, i. 39 
Linnaius' classification of animals, 

ii. 118 
classification of plants 

ii. 78 

designation of species, i. 41 

history of creation, i. 44 

system, i. 40 

Lubbock, Sir John, ii. 298 

Lyell, Charles, i. 126 

Lyell's history of creation, i. 128 


Magyars, ii. 309, 316 

Malays, ii. 308, 315 

Malthus' theory of population, i. IGl 

Mammalia, ii. 231, 239 

Man-apes, ii. 271, 27-5, 292 

Marsupials, ii. 236, 239, 290 

Matagenesis, i. 206 

Materialism, i. 35 

Matter, i. 22, ii. SCO 

Mechanical causes, i. 34, 74 

Mechanical conception of the uni- 
verse, i. 17, 74 

Mechanism, i. 37, 102 

Mediterranese, ii. 308, 321 

Medusas, ii. 143, 144 

Mesolithic period, ii. 14, 20 

Metamorphosis of the earth's strata, 
ii. 25 

Metamorphosis, i 90 

Migration, laws of, i. 373 

of organisms, i. 354 

of the human species, 

ii. 325 

theory of, i. 367 

Mind, i. 22; ii. 300 

development of the, ii. 344, 

Miocene period, ii. 15, 16 
Miracles, i. 22 
Molluscs, ii. 155, 160 
Monera, i. 184, 343; ii. 52, 278 
Mongols, ii. 308, 316 
Monism, i. 34 



Monistic conception of the universe, 

i. 20, 74 
MonocottyliE, ii. 82, 112 
Monoglottonio, ii. 327, 333 
Monogony, i. 183 
Monophylites, il. ii 
Monophyletio hypothesis of descent, 

ii. 44 
Monorrhina, ii. 203, 204 
Monosporogonia, i. 194 
Monotrema, ii. 234, 239 
Morphology, i. 21 
Morula, ii. 125, 127 
Moses' history of creation, i 37 
Moss animals, ii. 150, 162 
Mosses, ii. 82, 97 
Miiller, Fritz, i. 49, 73 ; ii. 174 
Miiller, Johannes, i. 312 ; ii. 203 
Muscinsi, ii. 82, 99 
Mussels, ii. 159, 100 
Myriapoda, ii. 182, 184 
Myxomycetes, ii. 51, CO 

Natural philosophy, i. 78 
Negroes, ii. 309, 313, 333 
Nemathelminthcs, ii. 149, 150 
Newton, i. 25, 106 
Non-amnionate, ii. 204, 209 
Nubians, ii. 308, 320 


CEcoLOGT, ii, 354 

Oken, Loreuz, i. 95 

Oken's history of development, i. 293 

philosophy of nature, i. 96 

theory of infusoria, i. 97 

protoplasm, i. 97 

Olynthus, ii. 141 
Ontogenesis, i. 293 
Ontogeny, i. 10 ; ii. 33 
Orang, ii. 271, 275 
Organisms, i. 5, 328 
Organs, i. 5 

Origin of language, ii. 302, 327 
Osseous fishes, ii. 208, 211 
Ovularia, ii. 132, 134 

Pachtoapdia, ii. 201 
Palfeolithio period, ii. 11, 14 
Palaeontology, 1. 54 
Palissy, i. 66 

Palm ferns, ii. 82, 110 

Pander, Christian, i. 294 

Papuans, ii. 310, 333 

Paradise, ii'. 325 

Parallelism of development, i. 313 

Parthenogenesis, i. 197 

Pedigree of amphibia, ii. 209 

— anamnia, ii. 209 

■ apes, ii. 270 

Perraean system, ii. 11, 14 
Petrifactions, i. 64 
Phanerogama, ii. 80, 82, 108 
Philosophy, i. 79 ; ii. 350 
Phylogeny, i. 10 ; ii. 33 
Phylum, ii. 42 
Physiology, i. 21 
Pithecoid, theory, ii. 356 
Placentalia, ii. 240, 244 
Planula, ii. 126, 135, 281 
Plana?a, ii. 125, 127 
Planseada, ii. 280 
Plasma, i. 185, 330 
Plasmogony, i. 339 
Plastids, i. 347 
Plastids, theory of, i. 347 
Platyelminthes, ii. 148, 150 
Platyrrhini, ii. 270, 272 
Pleistocene system, ii. 15 
Pliocene system, ii. 15, 16 
Polar man, ii. 30S, 317 
Polyglottal, ii. 327, 333 
Polynesians, ii, 308, 315 
Polyphyletio theory of descent, ii. 45 
Polyphylites, ii. 45, 303 
Polyps, ii. 142 
Polyp jellies, ii. 143, 144 
Polysporogonia, i. 193 
Population, number of, ii. 333 
Porifera, ii. 139, 144 
Primary mammals, ii. 239, 290 
Primary period, ii. 11, 14 
Primseval algae, ii. 82, 84 

animals, ii. 131, 132 

history of man, ii. 298 

men, ii. 325 

Primordial period, ii. 9, 14 
Prochordata, ii. 278 
Progenitors of man, ii. 279, 295 
Progress, i. 277, 283 
Promammalia, ii. 233, 239 
Propagation, L 183 

— amphigonic, i. 195 

monogenic, i. 183 

non-sexual, i. 183 



Propagation, sexual, i, 195 

— • virginal, i. 197 

Protamnia, ii. 289, 295 
Protamoebaj, ii. 52 
Prothallophytcs, ii. 80, 97 
Prothallus plants, ii. 80, 97 
Protista, ii. 48 
Protophyta, ii. 82, 85 
Protoplasma, i. 185, 330 
Protoplasts, ii. 51, 53 
Protozoa, u. 121, 131, 132 
Purpose in nature, i. 19 
Purposelessness in nature, i. 20 


Eadiata, ii, 120 
Eadiolaria, i. 333, 371 ; ii. 65 
llapacious animals, ii. 210, 2G0 
Eecent system, iL 15 
Eeptiles, ii. 222, 224 
Ehizopoda, ii. 51, CI 
Einged worms, ii. 149, 150 
Eodentia, ii. '241, 257 
Eomans, ii. 323, 331 
Rotatoria, ii. 149, 150 
Eotifera, ii. 150, 152 
liound worms, ii. 149, 150 
Eudimentary eyes, i. 13 

gristle, i. 12 

logs, i. 14 

lungs, i. 289 

mammary glands, 

i. 290 

muscles, i. 12 

nictitating membrane, 

i. 13 

organs, i. 12 

■ pistils, i. 15 

stamens, i, 15 

tails, i. 289 

teeth, i. 12 

wings, i. 287 

Sack wokms, ii. 283, 295 

Sauria, ii. 222 

Schaaffhausen, i. 110 

Schleiclier, August, i. 108 ; ii. 301 

Schleiden, J. M., i. 109 

Science, i. 9 ; ii. 335 

Scolecida, ii. 283, 295 

Sea stars, ii. 1G4, ICG 

cucumbers, ii, IGG, 171 

Sea dragons, ii. 20 1 

lilies, ii. ICG, 177 

nettles, ii. 141, 144 

urchins, ii. 166, 171 

Secondary period, ii. 14, 20 
Selection assthetic, i. 2G8 

artificial, i. 152, 170, 254 

homochromic, i. 2G3 

medical, i. 173 

military, i. 171 

musical, i. 267 

natural, i. 1G8, 255 

psychical, i. 269 

sexual, i. 265 

Spartan, i. 170 

Self-division, i, 191 
Semites, ii. 322, 330 
Serpents ii. 223 
Sexes, separation of, i. 241 
Sexual characters, i, 209, 2G5 
Silurian system, ii, 8, 14 
Slavonians, ii, 323, 331 
Snails, ii. 159, 160 
Soul, the, i. 71, ii. 343, 3C2 
Species, i. 41, 273, 301, 311 
Specific development, i. 311 
Spencer, Herbert, i, 119 ; ii. 307 
Sperma, i. 197 
Spiders, i. 180, 182 
Spirobranchia, ii. 157, IGO 
Sponges, ii. 139, 144 
Spores, formation of, i, 194 
Stemmed plants, ii, 2S0 
Straight-haired men, ii, 309, 314 
Struggle for life, i. ICl, 252 
Synamoeba, ii, 125, 280 
Systematic development, i, 313 
System of animals, ii, 132 

apes, ii, 270 

Arabians, ii, 330 

arachnida, ii, 182 

Arians, ii, 331 

arthropoda, ii. 132 

artioulata, ii. 177, 183 

catarrhiui, ii, 270 

coelenterata, ii. 144 

Crustacea, ii, 176 

didelphia, ii, 239 

echinoderma, ii, 166 

Egyptians, ii. 330 

fishes, ii, 208 

■ formations, ii. 15 

Germans, ii, 331 

gilled Insects, ii. 177 



System of Grfeoo-Romans, ii. 331 

Hamites, ii. 330 

hoofed animals, ii. 252 

human ancestors, ii. 295 

human races, ii. 308 

human species, ii. 308, 309 

Indians, ii. 331 

■ Indo-Germani, ii. 331 

insects, ii. 182 

mammalia, ii. 239 

mankind, ii. 295 

marsupials, ii. 239 

men and apes, ii. 271 

molluscs, ii. 160 

monodelphia, ii. 211 

organisms, ii. 74, 75 

placentalia, ii. 210 

plants, ii. 82 

platyrrhini, ii. 270 

protista, ii, 51 

reptiles, ii. 221: 

Semites, ii, 330 

Slavonians, ii. 331 

— spiders, ii. 182 

star fishes, ii. 167 

strata of the earth, ii. 15 

tracheata, ii. 182 

ungulata, ii. 252 

vegetable kingdom, ii. 83 

• vertebrata, ii. 201 

•worms, ii. 150 

zoophytes, ii. 144 


Tail of mah, i. 289, 308 
Tangles, ii. 61, 82 
Tartars, ii. 209, 317 • 
Teleology, i. 100, 291 
Teleostei, ii. 208, 211 
Teleological conception of the uni- 
verse, i. 20, 75 
Tertiary period, ii. 14, 16 
Thallophytes, ii. 80, 82 
Thickness of the earth's crust, ii. 19 
Thought, ii. 3G4 

Thread plants, ii. 82, 93 
Tocogony, i. 183 
Tortoises, ii. 225 
Tracheata, ii. 182 
Transition forms, ii. 338 
Transmutation, theory of, i. 4 
Treviianus, i. 92 
Trias system, ii. 12, 14 
Tuft-haii-ed men, ii. 307, 309 
Tunicata, ii. 152, 200 
Turbellaria, ii. 283 
Turks, ii. 309, 316 


linger, Franz, i. 109 
TJngulata, ii. 249, 252 
Unity in nature, i- 22, 338 
Uralians, ii. 309, 317 

Variability, i. 220 
Variation, i. 219 
Varieties, i. 276 
Vertebrata, ii. 195, 205 
Vital force, i. 22, 334 
Vitalistic conception of the universe, 
i. 18 


Wagnee, Andreas, i. 138 
Wagner, Moritz, i. 309 
"Wallace, Alfred, i. 135 
Wallace's chorology, i. 361 373 

theory of selection, i. 136 

Well's theory of selection, i. 150 
Whales, ii. 210, 251 
Will, freedom of the, i. 113, 237, 364 
Wolff's theory of development, i. 293 
Woolly-haired men, ii. 307, 309 
Worms, ii. 117, 150 


Zoophytes, ii. 130, 144 


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A New Magazine for Students and Cultivated Readers. 


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The growing importance of scientific knowledge to aU classes of thf" 
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